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path: root/drivers/usb/host/xhci.h
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2024-12-27xhci: Add command completion parameter supportMathias Nyman
xHC hosts can pass 24 bits of data with a command completion event TRB as the completion code only uses 8 bits of the 32 bit status field. Only Configure Endpoint, and Get Extended Property commands utilize this "command completion parameter" 24 bit field. For other command completion events the xHC should keep it RsvdZ. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241227120142.1035206-5-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06usb: xhci: Avoid queuing redundant Stop Endpoint commandsMichal Pecio
Stop Endpoint command on an already stopped endpoint fails and may be misinterpreted as a known hardware bug by the completion handler. This results in an unnecessary delay with repeated retries of the command. Avoid queuing this command when endpoint state flags indicate that it's stopped or halted and the command will fail. If commands are pending on the endpoint, their completion handlers will process cancelled TDs so it's done. In case of waiting for external operations like clearing TT buffer, the endpoint is stopped and cancelled TDs can be processed now. This eliminates practically all unnecessary retries because an endpoint with pending URBs is maintained in Running state by the driver, unless aforementioned commands or other operations are pending on it. This is guaranteed by xhci_ring_ep_doorbell() and by the fact that it is called every time any of those operations completes. The only known exceptions are hardware bugs (the endpoint never starts at all) and Stream Protocol errors not associated with any TRB, which cause an endpoint reset not followed by restart. Sounds like a bug. Generally, these retries are only expected to happen when the endpoint fails to start for unknown/no reason, which is a worse problem itself, and fixing the bug eliminates the retries too. All cases were tested and found to work as expected. SET_DEQ_PENDING was produced by patching uvcvideo to unlink URBs in 100us intervals, which then runs into this case very often. EP_HALTED was produced by restarting 'cat /dev/ttyUSB0' on a serial dongle with broken cable. EP_CLEARING_TT by the same, with the dongle on an external hub. Fixes: fd9d55d190c0 ("xhci: retry Stop Endpoint on buggy NEC controllers") CC: stable@vger.kernel.org Signed-off-by: Michal Pecio <michal.pecio@gmail.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-34-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06usb: xhci: Limit Stop Endpoint retriesMichal Pecio
Some host controllers fail to atomically transition an endpoint to the Running state on a doorbell ring and enter a hidden "Restarting" state, which looks very much like Stopped, with the important difference that it will spontaneously transition to Running anytime soon. A Stop Endpoint command queued in the Restarting state typically fails with Context State Error and the completion handler sees the Endpoint Context State as either still Stopped or already Running. Even a case of Halted was observed, when an error occurred right after the restart. The Halted state is already recovered from by resetting the endpoint. The Running state is handled by retrying Stop Endpoint. The Stopped state was recognized as a problem on NEC controllers and worked around also by retrying, because the endpoint soon restarts and then stops for good. But there is a risk: the command may fail if the endpoint is "stopped for good" already, and retries will fail forever. The possibility of this was not realized at the time, but a number of cases were discovered later and reproduced. Some proved difficult to deal with, and it is outright impossible to predict if an endpoint may fail to ever start at all due to a hardware bug. One such bug (albeit on ASM3142, not on NEC) was found to be reliably triggered simply by toggling an AX88179 NIC up/down in a tight loop for a few seconds. An endless retries storm is quite nasty. Besides putting needless load on the xHC and CPU, it causes URBs never to be given back, paralyzing the device and connection/disconnection logic for the whole bus if the device is unplugged. User processes waiting for URBs become unkillable, drivers and kworker threads lock up and xhci_hcd cannot be reloaded. For peace of mind, impose a timeout on Stop Endpoint retries in this case. If they don't succeed in 100ms, consider the endpoint stopped permanently for some reason and just give back the unlinked URBs. This failure case is rare already and work is under way to make it rarer. Start this work today by also handling one simple case of race with Reset Endpoint, because it costs just two lines to implement. Fixes: fd9d55d190c0 ("xhci: retry Stop Endpoint on buggy NEC controllers") CC: stable@vger.kernel.org Signed-off-by: Michal Pecio <michal.pecio@gmail.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-32-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06usb: xhci: simplify TDs start and end naming scheme in struct 'xhci_td'Niklas Neronin
Old names: * start_seg - last_trb_seg * first_trb - last_trb New names: * start_seg - end_seg * start_trb - end_trb A Transfer Descriptor (TD) in the xhci driver is a data structure that represents a single transaction to be performed by the USB host controller. This transaction is defined by TRBs from 'start_trb' in 'start_seg' to 'end_trb' in 'end_seg'. The terms "start" and "end" were chosen over "first" and "last" for ease of searching within the codebase. The ring structure uses 'first_seg' and 'last_seg', while the TD structure uses 'start_seg' and 'end_seg'. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-24-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06xhci: Don't issue Reset Device command to Etron xHCI hostKuangyi Chiang
Sometimes the hub driver does not recognize the USB device connected to the external USB2.0 hub when the system resumes from S4. After the SetPortFeature(PORT_RESET) request is completed, the hub driver calls the HCD reset_device callback, which will issue a Reset Device command and free all structures associated with endpoints that were disabled. This happens when the xHCI driver issue a Reset Device command to inform the Etron xHCI host that the USB device associated with a device slot has been reset. Seems that the Etron xHCI host can not perform this command correctly, affecting the USB device. To work around this, the xHCI driver should obtain a new device slot with reference to commit 651aaf36a7d7 ("usb: xhci: Handle USB transaction error on address command"), which is another way to inform the Etron xHCI host that the USB device has been reset. Add a new XHCI_ETRON_HOST quirk flag to invoke the workaround in xhci_discover_or_reset_device(). Fixes: 2a8f82c4ceaf ("USB: xhci: Notify the xHC when a device is reset.") Cc: stable@vger.kernel.org Signed-off-by: Kuangyi Chiang <ki.chiang65@gmail.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-19-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06usb: xhci: remove option to change a default ring's TRB cycle bitNiklas Neronin
The TRB cycle bit indicates TRB ownership by the Host Controller (HC) or Host Controller Driver (HCD). New rings are initialized with 'cycle_state' equal to one, and all its TRBs' cycle bits are set to zero. When handling ring expansion, set the source ring cycle bits to the same value as the destination ring. Move the cycle bit setting from xhci_segment_alloc() to xhci_link_rings(), and remove the 'cycle_state' argument from xhci_initialize_ring_info(). The xhci_segment_alloc() function uses kzalloc_node() to allocate segments, ensuring that all TRB cycle bits are initialized to zero. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-12-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06usb: xhci: introduce macro for ring segment list iterationNiklas Neronin
Add macro to streamline and standardize the iteration over ring segment list. xhci_for_each_ring_seg(): Iterates over the entire ring segment list. The xhci_free_segments_for_ring() function's while loop has not been updated to use the new macro. This function has some underlying issues, and as a result, it will be handled separately in a future patch. Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-11-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06xhci: add stream context tracingMathias Nyman
Show stream id, stream context type (SCT), ring dequeue pointer and the DMA address of the stream context during stream allocation Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-8-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-06xhci: Add Isochronous TRB fields to TRB tracerMathias Nyman
In addition to Normal TRB fields the Isoch TRBs have a SIA flag, Frame ID, TLBPC and TBC fields. Add these fields to tracing output Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241106101459.775897-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-21Merge 6.12-rc4 into usb-nextGreg Kroah-Hartman
We need the USB fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-17xhci: Fix incorrect stream context type macroMathias Nyman
The stream contex type (SCT) bitfield is used both in the stream context data structure, and in the 'Set TR Dequeue pointer' command TRB. In both cases it uses bits 3:1 The SCT_FOR_TRB(p) macro used to set the stream context type (SCT) field for the 'Set TR Dequeue pointer' command TRB incorrectly shifts the value 1 bit left before masking the three bits. Fix this by first masking and rshifting, just like the similar SCT_FOR_CTX(p) macro does This issue has not been visibile as the lost bit 3 is only used with secondary stream arrays (SSA). Xhci driver currently only supports using a primary stream array with Linear stream addressing. Fixes: 95241dbdf828 ("xhci: Set SCT field for Set TR dequeue on streams") Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20241016140000.783905-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-17xhci: add helper to stop endpoint and wait for completionMathias Nyman
Expose xhci_stop_endpoint_sync() which is a synchronous variant of xhci_queue_stop_endpoint(). This is useful for client drivers that are using the secondary interrupters, and need to stop the current endpoint session. This does not go through the normal xhci_handle_cmd_stop_ep() command completion handler, because it utilizes the completion path to achieve synchronous behavior. Users of this API are primarily intended to be clients that maintain their own transfer rings, such as in the case of USB audio offload. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Link: https://lore.kernel.org/r/20241015212915.1206789-3-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-11usb: xhci: fix loss of data on Cadence xHCPawel Laszczak
Streams should flush their TRB cache, re-read TRBs, and start executing TRBs from the beginning of the new dequeue pointer after a 'Set TR Dequeue Pointer' command. Cadence controllers may fail to start from the beginning of the dequeue TRB as it doesn't clear the Opaque 'RsvdO' field of the stream context during 'Set TR Dequeue' command. This stream context area is where xHC stores information about the last partially executed TD when a stream is stopped. xHC uses this information to resume the transfer where it left mid TD, when the stream is restarted. Patch fixes this by clearing out all RsvdO fields before initializing new Stream transfer using a 'Set TR Dequeue Pointer' command. Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver") cc: stable@vger.kernel.org Signed-off-by: Pawel Laszczak <pawell@cadence.com> Reviewed-by: Peter Chen <peter.chen@kernel.org> Link: https://lore.kernel.org/r/PH7PR07MB95386A40146E3EC64086F409DD9D2@PH7PR07MB9538.namprd07.prod.outlook.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-05xhci: support setting interrupt moderation IMOD for secondary interruptersMathias Nyman
Allow creators of seconday interrupters to specify the interrupt moderation interval value in nanoseconds when creating the interrupter. If not sure what value to use then use the xhci driver default xhci->imod_interval Suggested-by: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240905143300.1959279-13-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-05usb: xhci: make 'sbrn' a local variableNiklas Neronin
Variable 'sbrn' is used to store the Serial Bus Release Number, which is then only used for a debug message. Thus, 'sbrn' can be a local variable and assigned after the primary HCD check. The SBRN debug message is only printed when a primary HCD is setup. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240905143300.1959279-8-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-05usb: xhci: remove unused variables from struct 'xhci_hcd'Niklas Neronin
Variables 'max_slots', 'max_ports', 'isoc_threshold' and 'event_ring_max' are never set or used. Thus, remove them. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240905143300.1959279-7-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-05xhci: Remove unused function declarationsYue Haibing
Commit 674f8438c121 ("xhci: split handling halted endpoints into two steps") removed xhci_cleanup_stalled_ring() but left declaration. Commit 25355e046d29 ("xhci: use generic command timer for stop endpoint commands.") left behind xhci_stop_endpoint_command_watchdog(). Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240905143300.1959279-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-03usb: Add tunnel_mode parameter to usb device structureMathias Nyman
Add 'tunnel_mode' enum to usb device structure to describe if a USB3 link is tunneled over USB4, or connected directly using native USB2/USB3 protocols. Tunneled devices depend on USB4 NHI host to maintain the tunnel. Knowledge about tunneled devices is important to ensure correct suspend and resume order between USB4 hosts and tunneled devices. i.e. make sure tunnel is up before the USB device using it resumes. USB hosts such as xHCI may have vendor specific ways to detect tunneled connections. This 'tunnel_mode' parameter can be set by USB3 host driver during hcd->driver->update_device(hcd, udev) callback. tunnel_mode can be set to: USB_LINK_UNKNOWN = 0 USB_LINK_NATIVE USB_LINK_TUNNELED USB_LINK_UNKNOWN is used in case host is not capable of detecting tunneled links. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240830152630.3943215-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-03xhci: Add USB4 tunnel detection for USB3 devices on Intel hostsMathias Nyman
Knowledge about tunneled devices is useful in order to correctly describe the relationship between tunneled USB3 device and USB4 Host Interface, ensuring proper suspend and resume order, and to be able to power down Thunderbolt if there is no need for tunneling. Intel hosts share if a USB3 connection is native or tunneled via vendor specific "SPR eSS PORT" registers. These vendor registers are available if host supports a vendor specific SPR shadow extended capability with ID 206. Registers are per USB3 port and 0x20 apart. Knowing the tunneling status of the device connected to roothub is enough as all its children will have the same status. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240830152630.3943215-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-07xhci-pci: Make xhci-pci-renesas a proper modular driverBen Hutchings
If CONFIG_USB_XHCI_PCI_RENESAS is enabled, xhci-pci conditionally calls into the xhci-pci-renesas module, which means both modules must be loaded to use any xHCI PCI controller. The MODULE_FIRMWARE declaration in the base xhci-pci module causes initramfs-tools to check for and warn about missing firmware for the Renesas xHCI controllers, when any xHCI PCI controller is present. And because of the previous oddity, simply moving this declaration to xhci-pci-renesas wouldn't help. To fix this, reverse the relationship between the modules: - Remove the quirk for the Renesas xHCIs, and the driver_data structure used only for them - In xhci-pci: - Rename xhci_pci_probe() to xhci_pci_common_probe() - Export xhci_pci_common_probe() and xhci_pci_remove() - Use a new probe function that rejects the Renesas xHCIs and then calls the common probe function - In xhci-pci-renesas: - Stop exporting renesas_xhci_check_request_fw() - Add a probe function that calls renesas_xhci_check_request_fw() followed by xhci_pci_common_probe() - Add and register a new pci_driver matching only the Renesas xHCIs and using its own probe function, but with other operations the same as in xhci-pci - Make CONFIG_USB_XHCI_PCI_RENESAS depend on CONFIG_USB_XHCI_PCI, not the other way around Finally, move the MODULE_FIRMWARE declaration to xhci-pci-renesas. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Tested-by: Cyril Brulebois <cyril@debamax.com> Link: https://lore.kernel.org/r/ZqqfXYRJf7kGaqus@decadent.org.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27xhci: sort out TRB Endpoint ID bitfield macrosMathias Nyman
xhci macros that read and write endpoint ID bitfields of TRBs are mixing the 1-based Endpoint ID as described in the xHCI specification, and 0-based endpoint index used by driver as an array index. Sort this out by naming macros that deal with 1 based Endpoint ID fields to *_EP_ID_*, and 0 based endpoint index values to *_EP_INDEX_*. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240626124835.1023046-22-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27usb: xhci: move link chain bit quirk checks into one helper function.Niklas Neronin
Older 0.95 xHCI hosts and some other specific newer hosts require the chain bit to be set for Link TRBs even if the link TRB is not in the middle of a transfer descriptor (TD). move the checks for all those cases into one xhci_link_chain_quirk() function to clean up and avoid code duplication. No functional changes. [skip renaming chain_links flag, reword commit message -Mathias] Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240626124835.1023046-10-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27usb: xhci: remove 'num_trbs' from struct 'xhci_td'Niklas Neronin
Remove 'num_trbs' from 'xhci_td' as it's no longer used following the removal of 'num_trbs_free' tracking in commit 2710f8186f88 ("xhci: Stop unnecessary tracking of free trbs in a ring"). Tracking of 'num_trbs_free' is still performed in xhci DbC, but it does not utilize 'num_trbs'. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240626124835.1023046-6-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-20xhci: Add a quirk for writing ERST in high-low orderDaehwan Jung
This quirk is for the controller that has a limitation in supporting separate ERSTBA_HI and ERSTBA_LO programming. It's supported when the ERSTBA is programmed ERSTBA_HI before ERSTBA_LO. That's because the internal initialization of event ring fetches the "Event Ring Segment Table Entry" based on the indication of ERSTBA_LO written. Signed-off-by: Daehwan Jung <dh10.jung@samsung.com> Link: https://lore.kernel.org/r/1718019553-111939-3-git-send-email-dh10.jung@samsung.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-12xhci: Handle TD clearing for multiple streams caseHector Martin
When multiple streams are in use, multiple TDs might be in flight when an endpoint is stopped. We need to issue a Set TR Dequeue Pointer for each, to ensure everything is reset properly and the caches cleared. Change the logic so that any N>1 TDs found active for different streams are deferred until after the first one is processed, calling xhci_invalidate_cancelled_tds() again from xhci_handle_cmd_set_deq() to queue another command until we are done with all of them. Also change the error/"should never happen" paths to ensure we at least clear any affected TDs, even if we can't issue a command to clear the hardware cache, and complain loudly with an xhci_warn() if this ever happens. This problem case dates back to commit e9df17eb1408 ("USB: xhci: Correct assumptions about number of rings per endpoint.") early on in the XHCI driver's life, when stream support was first added. It was then identified but not fixed nor made into a warning in commit 674f8438c121 ("xhci: split handling halted endpoints into two steps"), which added a FIXME comment for the problem case (without materially changing the behavior as far as I can tell, though the new logic made the problem more obvious). Then later, in commit 94f339147fc3 ("xhci: Fix failure to give back some cached cancelled URBs."), it was acknowledged again. [Mathias: commit 94f339147fc3 ("xhci: Fix failure to give back some cached cancelled URBs.") was a targeted regression fix to the previously mentioned patch. Users reported issues with usb stuck after unmounting/disconnecting UAS devices. This rolled back the TD clearing of multiple streams to its original state.] Apparently the commit author was aware of the problem (yet still chose to submit it): It was still mentioned as a FIXME, an xhci_dbg() was added to log the problem condition, and the remaining issue was mentioned in the commit description. The choice of making the log type xhci_dbg() for what is, at this point, a completely unhandled and known broken condition is puzzling and unfortunate, as it guarantees that no actual users would see the log in production, thereby making it nigh undebuggable (indeed, even if you turn on DEBUG, the message doesn't really hint at there being a problem at all). It took me *months* of random xHC crashes to finally find a reliable repro and be able to do a deep dive debug session, which could all have been avoided had this unhandled, broken condition been actually reported with a warning, as it should have been as a bug intentionally left in unfixed (never mind that it shouldn't have been left in at all). > Another fix to solve clearing the caches of all stream rings with > cancelled TDs is needed, but not as urgent. 3 years after that statement and 14 years after the original bug was introduced, I think it's finally time to fix it. And maybe next time let's not leave bugs unfixed (that are actually worse than the original bug), and let's actually get people to review kernel commits please. Fixes xHC crashes and IOMMU faults with UAS devices when handling errors/faults. Easiest repro is to use `hdparm` to mark an early sector (e.g. 1024) on a disk as bad, then `cat /dev/sdX > /dev/null` in a loop. At least in the case of JMicron controllers, the read errors end up having to cancel two TDs (for two queued requests to different streams) and the one that didn't get cleared properly ends up faulting the xHC entirely when it tries to access DMA pages that have since been unmapped, referred to by the stale TDs. This normally happens quickly (after two or three loops). After this fix, I left the `cat` in a loop running overnight and experienced no xHC failures, with all read errors recovered properly. Repro'd and tested on an Apple M1 Mac Mini (dwc3 host). On systems without an IOMMU, this bug would instead silently corrupt freed memory, making this a security bug (even on systems with IOMMUs this could silently corrupt memory belonging to other USB devices on the same controller, so it's still a security bug). Given that the kernel autoprobes partition tables, I'm pretty sure a malicious USB device pretending to be a UAS device and reporting an error with the right timing could deliberately trigger a UAF and write to freed memory, with no user action. [Mathias: Commit message and code comment edit, original at:] https://lore.kernel.org/linux-usb/20240524-xhci-streams-v1-1-6b1f13819bea@marcan.st/ Fixes: e9df17eb1408 ("USB: xhci: Correct assumptions about number of rings per endpoint.") Fixes: 94f339147fc3 ("xhci: Fix failure to give back some cached cancelled URBs.") Fixes: 674f8438c121 ("xhci: split handling halted endpoints into two steps") Cc: stable@vger.kernel.org Cc: security@kernel.org Reviewed-by: Neal Gompa <neal@gompa.dev> Signed-off-by: Hector Martin <marcan@marcan.st> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240611120610.3264502-5-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01usb: xhci: compact 'trb_in_td()' argumentsNiklas Neronin
Pass pointer to the TD (struct xhci_td *) directly, instead of its components separately. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-19-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01xhci: remove XHCI_TRUST_TX_LENGTH quirkMathias Nyman
If this quirk was set then driver would treat transfer events with 'Success' completion code as 'Short packet' if there were untransferred bytes left. This is so common that turn it into default behavior. xhci_warn_ratelimited() is no longer used after this, so remove it. A success event with untransferred bytes left doesn't always mean a misbehaving controller. If there was an error mid a multi-TRB TD it's allowed to issue a success event for the last TRB in that TD. See xhci 1.2 spec 4.9.1 Transfer Descriptors "Note: If an error is detected while processing a multi-TRB TD, the xHC shall generate a Transfer Event for the TRB that the error was detected on with the appropriate error Condition Code, then may advance to the next TD. If in the process of advancing to the next TD, a Transfer TRB is encountered with its IOC flag set, then the Condition Code of the Transfer Event generated for that Transfer TRB should be Success, because there was no error actually associated with the TRB that generated the Event. However, an xHC implementation may redundantly assert the original error Condition Code." Co-developed-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-10-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01xhci: improve PORTSC register debugging outputMathias Nyman
Print the full hex value of PORTSC register in addition to the human readable decoded string while debugging PORTSC value. If PORTSC value is 0xffffffff then don't decode it. This lets us inspect Rsvd bits of PORTSC. Same is done for USBSTS register values. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-9-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01usb: xhci: remove redundant variable 'erst_size'Niklas Neronin
'erst_size' represents the maximum capacity of entries that ERST can hold, while 'num_entries' indicates the actual number of entries currently held in the ERST. These two values are identical because the xhci driver does not support ERST expansion. Thus, 'erst_size' is removed. Suggested-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-7-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01usb: xhci: check if 'requested segments' exceeds ERST capacityNiklas Neronin
Check if requested segments ('segs' or 'ERST_DEFAULT_SEGS') exceeds the maximum amount ERST supports. When 'segs' is '0', 'ERST_DEFAULT_SEGS' is used instead. But both values may not exceed ERST max. Macro 'ERST_MAX_SEGS' is renamed to 'ERST_DEFAULT_SEGS'. The new name better represents the macros, which is the number of Event Ring segments to allocate, when the amount is not specified. Additionally, rename and change xhci_create_secondary_interrupter()'s argument 'int num_segs' to 'unsigned int segs'. This makes it the same as its counter part in xhci_alloc_interrupter(). Fixes: c99b38c41234 ("xhci: add support to allocate several interrupters") Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-01xhci: stored cached port capability values in one placeMathias Nyman
Port capability flags for USB2 ports have been cached in an u32 xhci->ext_caps[] array long before the driver had struct xhci_port and struct xhci_port_cap structures. Move these cached USB2 port capability values together with the other port capability values into struct xhci_port_cap cability structure. This also gets rid of the cumbersome way of mapping port to USB2 capability based on portnum as each port has a pointer to its capability structure. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240429140245.3955523-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-02xhci: save slot ID in struct 'xhci_port'Niklas Neronin
Slot ID is a index of a virtual device in struct 'xhci_hcd->devs[]'. Previously, to get the slot ID associated with a port, we had to loop through all devices and compare ports, which is very inefficient. Instead, the slot ID (of the device which is directly connected to the port), is added to the its corresponding 'xhci_port' struct. As a result, finding the port's device is quick and easy. Function 'xhci_find_slot_id_by_port()' is removed, as it is no longer needed. Signed-off-by: Niklas Neronin <niklas.neronin@intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240229141438.619372-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-02xhci: replace real & fake port with pointer to root hub portNiklas Neronin
Variables real & fake port do not convey their purpose, thus they are replaced with a pointer to the root hub port 'struct xhci_port *rhub_port'. 'rhub_port' contains real & fake ports in zero-based format, which happens to be more widely used inside the xHCI driver: - 'real_port' is ('rhub_port->hw_portnum' + 1) - 'fake_port' is ('rhub_port->hcd_portnum' + 1) One reason for real port being one-based, is to signal other functions in case struct 'xhci_virt_device' initialization failed, in this case the value will remain 0. This is no longer needed, instead we check whether or not 'rhub_port' is 'NULL'. Signed-off-by: Niklas Neronin <niklas.neronin@intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240229141438.619372-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-19Revert "xhci: add helper to stop endpoint and wait for completion"Greg Kroah-Hartman
This reverts commit 9affb1d9a9d9918adff519a129daba5e369dd741. It's not ready to be merged, based on reviews. Reported-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/96ab6033-2cb9-daa7-ddad-090138896739@linux.intel.com Cc: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-17xhci: add helper to stop endpoint and wait for completionMathias Nyman
Expose xhci_stop_endpoint_sync() which is a synchronous variant of xhci_queue_stop_endpoint(). This is useful for client drivers that are using the secondary interrupters, and need to stop/clean up the current session. The stop endpoint command handler will also take care of cleaning up the ring. Modifications to repurpose the new API into existing stop endpoint sequences was implemented by Wesley Cheng. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Co-developed-by: Wesley Cheng <quic_wcheng@quicinc.com> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Link: https://lore.kernel.org/r/20240217001017.29969-11-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-17xhci: make isoc_bei_interval variable interrupter specific.Mathias Nyman
isoc_bei_interval is used to balance how often completed isochronous events cause interrupts. If interval is too large then the event ring may fill up before the completed isoc TRBs are handled. isoc_bei_interval is tuned based on how full the event ring is. isoc_bei_interval variable needs to be per interrupter as with several interrupters each one has its own event ring. move isoc_bei_interval variable to the interrupter structure. if a secondary interrupter does not care about this feature then keep isoc_bei_interval 0. Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Link: https://lore.kernel.org/r/20240217001017.29969-4-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-17xhci: Add interrupt pending autoclear flag to each interrupterMathias Nyman
Each interrupter has an interrupt pending (IP) bit that should be cleared in the interrupt handler. This is done automatically for systems using MSI/MSI-X interrupts. Secondary interrupters used by audio offload may not actually trigger MSI/MSI-X messages, so driver may need to clear the IP bit manually for these, even if the primary interrupter IP is cleared automatically. Add an ip_autoclear flag to each interrupter that driver can configure when requesting an interrupt for that xHC interrupter, and move the interrupt pending clearing code to its own helper function. Use this ip_autoclear flag instead of the current hcd->msi_enabled to check if IP flag is cleared by software. [Moved ip_autoclear into xhci and set based on msi_enabled -wcheng] Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Link: https://lore.kernel.org/r/20240217001017.29969-2-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-04Merge 6.8-rc3 into usb-nextGreg Kroah-Hartman
We need the USB fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-27XHCI: Separate PORT and CAPs macros into dedicated fileFrank Li
Split the PORT and CAPs macro definitions into a separate file to facilitate sharing with other files without the need to include the entire xhci.h. Signed-off-by: Frank Li <Frank.Li@nxp.com> Link: https://lore.kernel.org/r/20240124152525.3910311-2-Frank.Li@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-27xhci: process isoc TD properly when there was a transaction error mid TD.Mathias Nyman
The last TRB of a isoc TD might not trigger an event if there was an error event for a TRB mid TD. This is seen on a NEC Corporation uPD720200 USB 3.0 Host After an error mid a multi-TRB TD the xHC should according to xhci 4.9.1 generate events for passed TRBs with IOC flag set if it proceeds to the next TD. This event is either a copy of the original error, or a "success" transfer event. If that event is missing then the driver and xHC host get out of sync as the driver is still expecting a transfer event for that first TD, while xHC host is already sending events for the next TD in the list. This leads to "Transfer event TRB DMA ptr not part of current TD" messages. As a solution we tag the isoc TDs that get error events mid TD. If an event doesn't match the first TD, then check if the tag is set, and event points to the next TD. In that case give back the fist TD and process the next TD normally Make sure TD status and transferred length stay valid in both cases with and without final TD completion event. Reported-by: Michał Pecio <michal.pecio@gmail.com> Closes: https://lore.kernel.org/linux-usb/20240112235205.1259f60c@foxbook/ Tested-by: Michał Pecio <michal.pecio@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20240125152737.2983959-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-04xhci: add support to allocate several interruptersMathias Nyman
Modify the XHCI drivers to accommodate for handling multiple event rings in case there are multiple interrupters. Add the required APIs so clients are able to allocate/request for an interrupter ring, and pass this information back to the client driver. This allows for users to handle the resource accordingly, such as passing the event ring base address to an audio DSP. There is no actual support for multiple MSI/MSI-X vectors. [export xhci_initialize_ring_info() -wcheng] Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> Link: https://lore.kernel.org/r/20240102214549.22498-2-quic_wcheng@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-04xhci: change 'msix_count' to encompass MSI or MSI-X vectorsNiklas Neronin
Instead of variable 'msix_count' containing the number of MSI-X vectors, now it can contains MSI or MSI-X vector amount. Because both interrupt methods allow several vectors. Thus, 'msix_count' is renamed to 'nvecs'. Additionally, instead of storing the maximum possible vector amount, now it stores the amount of successfully allocated vectors, or negative integer on allocation failure. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231201150647.1307406-16-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-23usb: xhci: Add timeout argument in address_device USB HCD callbackHardik Gajjar
- The HCD address_device callback now accepts a user-defined timeout value in milliseconds, providing better control over command execution times. - The default timeout value for the address_device command has been set to 5000 ms, aligning with the USB 3.2 specification. However, this timeout can be adjusted as needed. - The xhci_setup_device function has been updated to accept the timeout value, allowing it to specify the maximum wait time for the command operation to complete. - The hub driver has also been updated to accommodate the newly added timeout parameter during the SET_ADDRESS request. Signed-off-by: Hardik Gajjar <hgajjar@de.adit-jv.com> Reviewed-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231027152029.104363-1-hgajjar@de.adit-jv.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-11-03Merge tag 'usb-6.7-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb Pull USB/Thunderbolt updates from Greg KH: "Here is the "big" set of USB and Thunderbolt changes for 6.7-rc1. Nothing really major in here, just lots of constant development for new hardware. Included in here are: - Thunderbolt (i.e. USB4) fixes for reported issues and support for new hardware types and devices - USB typec additions of new drivers and cleanups for some existing ones - xhci cleanups and expanded tracing support and some platform specific updates - USB "La Jolla Cove Adapter (LJCA)" support added, and the gpio, spi, and i2c drivers for that type of device (all acked by the respective subsystem maintainers.) - lots of USB gadget driver updates and cleanups - new USB dwc3 platforms supported, as well as other dwc3 fixes and cleanups - USB chipidea driver updates - other smaller driver cleanups and additions, full details in the shortlog All of these have been in the linux-next tree for a while with no reported problems" * tag 'usb-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (167 commits) usb: gadget: uvc: Add missing initialization of ssp config descriptor usb: storage: set 1.50 as the lower bcdDevice for older "Super Top" compatibility usb: raw-gadget: report suspend, resume, reset, and disconnect events usb: raw-gadget: don't disable device if usb_ep_queue fails usb: raw-gadget: properly handle interrupted requests usb:cdnsp: remove TRB_FLUSH_ENDPOINT command usb: gadget: aspeed_udc: Convert to platform remove callback returning void dt-bindings: usb: fsa4480: Add compatible for OCP96011 usb: typec: fsa4480: Add support to swap SBU orientation dt-bindings: usb: fsa4480: Add data-lanes property to endpoint usb: typec: tcpm: Fix NULL pointer dereference in tcpm_pd_svdm() Revert "dt-bindings: usb: Add bindings for multiport properties on DWC3 controller" Revert "dt-bindings: usb: qcom,dwc3: Add bindings for SC8280 Multiport" thunderbolt: Fix one kernel-doc comment usb: gadget: f_ncm: Always set current gadget in ncm_bind() usb: core: Remove duplicated check in usb_hub_create_port_device usb: typec: tcpm: Add additional checks for contaminant arm64: dts: rockchip: rk3588s: Add USB3 host controller usb: dwc3: add optional PHY interface clocks dt-bindings: usb: add rk3588 compatible to rockchip,dwc3 ...
2023-10-30Merge tag 'hardening-v6.7-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: "One of the more voluminous set of changes is for adding the new __counted_by annotation[1] to gain run-time bounds checking of dynamically sized arrays with UBSan. - Add LKDTM test for stuck CPUs (Mark Rutland) - Improve LKDTM selftest behavior under UBSan (Ricardo Cañuelo) - Refactor more 1-element arrays into flexible arrays (Gustavo A. R. Silva) - Analyze and replace strlcpy and strncpy uses (Justin Stitt, Azeem Shaikh) - Convert group_info.usage to refcount_t (Elena Reshetova) - Add __counted_by annotations (Kees Cook, Gustavo A. R. Silva) - Add Kconfig fragment for basic hardening options (Kees Cook, Lukas Bulwahn) - Fix randstruct GCC plugin performance mode to stay in groups (Kees Cook) - Fix strtomem() compile-time check for small sources (Kees Cook)" * tag 'hardening-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (56 commits) hwmon: (acpi_power_meter) replace open-coded kmemdup_nul reset: Annotate struct reset_control_array with __counted_by kexec: Annotate struct crash_mem with __counted_by virtio_console: Annotate struct port_buffer with __counted_by ima: Add __counted_by for struct modsig and use struct_size() MAINTAINERS: Include stackleak paths in hardening entry string: Adjust strtomem() logic to allow for smaller sources hardening: x86: drop reference to removed config AMD_IOMMU_V2 randstruct: Fix gcc-plugin performance mode to stay in group mailbox: zynqmp: Annotate struct zynqmp_ipi_pdata with __counted_by drivers: thermal: tsens: Annotate struct tsens_priv with __counted_by irqchip/imx-intmux: Annotate struct intmux_data with __counted_by KVM: Annotate struct kvm_irq_routing_table with __counted_by virt: acrn: Annotate struct vm_memory_region_batch with __counted_by hwmon: Annotate struct gsc_hwmon_platform_data with __counted_by sparc: Annotate struct cpuinfo_tree with __counted_by isdn: kcapi: replace deprecated strncpy with strscpy_pad isdn: replace deprecated strncpy with strscpy NFS/flexfiles: Annotate struct nfs4_ff_layout_segment with __counted_by nfs41: Annotate struct nfs4_file_layout_dsaddr with __counted_by ...
2023-10-21usb: xhci: Implement xhci_handshake_check_state() helperUdipto Goswami
In some situations where xhci removal happens parallel to xhci_handshake, we encounter a scenario where the xhci_handshake can't succeed, and it polls until timeout. If xhci_handshake runs until timeout it can on some platforms result in a long wait which might lead to a watchdog timeout. Add a helper that checks xhci status during the handshake, and exits if set state is entered. Use this helper in places where xhci_handshake is called unlocked and has a long timeout. For example xhci command timeout and xhci reset. [commit message and code comment rewording -Mathias] Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-18-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-21xhci: Clean up xhci_{alloc,free}_erst() declarationsLukas Wunner
xhci_alloc_erst() has global scope even though it's only used in xhci-mem.c. Declare it static. xhci_free_erst() was removed by commit b17a57f89f69 ("xhci: Refactor interrupter code for initial multi interrupter support."), but a declaration in xhci.h still remains. Drop it. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-12-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-21xhci: Clean up stale comment on ERST_SIZE macroLukas Wunner
Commit ebd88cf50729 ("xhci: Remove unused defines for ERST_SIZE and ERST_ENTRIES") removed the ERST_SIZE macro but retained a code comment explaining the quantity chosen in the macro. Remove the code comment as well. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-11-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-21xhci: Clean up ERST_PTR_MASK inversionLukas Wunner
Mathias notes that the ERST_PTR_MASK macro is named as if it's masking the Event Ring Dequeue Pointer in the ERDP register, but in actuality it's masking the inverse. Invert the macro's value for clarity. Migrate it to the modern GENMASK_ULL() syntax to avoid u64 casts. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-10-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-21xhci: Use more than one Event Ring segmentJonathan Bell
Users have reported log spam created by "Event Ring Full" xHC event TRBs. These are caused by interrupt latency in conjunction with a very busy set of devices on the bus. The errors are benign, but throughput will suffer as the xHC will pause processing of transfers until the Event Ring is drained by the kernel. Commit dc0ffbea5729 ("usb: host: xhci: update event ring dequeue pointer on purpose") mitigated the issue by advancing the Event Ring Dequeue Pointer already after half a segment has been processed. Nevertheless, providing a larger Event Ring would be useful to cope with load peaks. Expand the number of event TRB slots available by increasing the number of Event Ring segments in the ERST. Controllers have a hardware-defined limit as to the number of ERST entries they can process, but with up to 32k it can be excessively high (sec 5.3.4). So cap the actual number at 2 (configurable through the ERST_MAX_SEGS macro), which seems like a reasonable quantity. It is supported by any xHC because the limit in the HCSPARAMS2 register is defined as a power of 2. Renesas uPD720201 and VIA VL805 controllers do not support more than 2 ERST entries. An alternative to increasing the number of Event Ring segments would be an increase of the segment size. But that requires allocating multiple contiguous pages, which may be impossible if memory is fragmented. Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20231019102924.2797346-6-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>