lwn.git/drivers/gpu/vga/vga_switcheroo.c, branch v4.11

vga_switcheroo: Sphinxify docs

2016-07-12T14:14:36+00:00

Fix up formatting glitches remaining after the automatic rst conversion. Cc: Jonathan Corbet Cc: Jani Nikula Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/3a369602ae35fdbf5e4a12f7e172088c89fa27bb.1468225027.git.lukas@wunner.de

vga_switcheroo: Support deferred probing of audio clients

2016-05-31T11:16:22+00:00

Daniel Vetter pointed out that vga_switcheroo_client_probe_defer() could be needed by audio clients as well. To avoid mistakes when someone adds conditions for these in the future, constrain the single existing condition to VGA clients by checking for PCI_BASE_CLASS_DISPLAY. This encompasses both PCI_CLASS_DISPLAY_VGA as well as PCI_CLASS_DISPLAY_3D, which is used by some Nvidia Optimus GPUs. Any future checks for audio clients should then be constrained to PCI_BASE_CLASS_MULTIMEDIA. v6: Spun out from commit introducing vga_switcheroo_client_probe_defer() to keep it a pure refactoring change. (Emil Velikov, Jani Nikula) Cc: Daniel Vetter Cc: Emil Velikov Cc: Jani Nikula Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/358d58490eb9dda5f270d844b0dce511a2a20828.1464685538.git.lukas@wunner.de

vga_switcheroo: Add helper for deferred probing

2016-05-31T11:15:57+00:00

So far we've got one condition when DRM drivers need to defer probing on a dual GPU system and it's coded separately into each of the relevant drivers. As suggested by Daniel Vetter, deduplicate that code in the drivers and move it to a new vga_switcheroo helper. This yields better encapsulation of concepts and lets us add further checks in a central place. (The existing check pertains to pre-retina MacBook Pros and an additional check is expected to be needed for retinas.) One might be tempted to check deferred probing conditions in vga_switcheroo_register_client(), but this is usually called fairly late during driver load. The GPU is fully brought up and ready for switching at that point. On boot the ->probe hook is potentially called dozens of times until it finally succeeds, and each time we'd repeat bringup and teardown of the GPU, lengthening boot time considerably and cluttering logfiles. A separate helper is therefore needed which can be called right at the beginning of the ->probe hook. Note that amdgpu currently does not call this helper as the AMD GPUs built into MacBook Pros are only supported by radeon so far. v2: This helper could eventually be used by audio clients as well, so rephrase kerneldoc to refer to "client" instead of "GPU" and move the single existing check in an if block specific to PCI_CLASS_DISPLAY_VGA devices. Move documentation on that check from kerneldoc to a comment. (Daniel Vetter) v3: Mandate in kerneldoc that registration of client shall only happen after calling this helper. (Daniel Vetter) v4: Rebase on 412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when amdkfd not loaded") v5: Some Optimus GPUs use PCI_CLASS_DISPLAY_3D, make sure those are matched as well. (Emil Velikov) v6: The if-condition referring to PCI_BASE_CLASS_DISPLAY may be considered a functional change. Move to a separate commit to keep this a pure refactoring change. (Emil Velikov, Jani Nikula) Cc: Daniel Vetter Cc: Ben Skeggs Cc: Alex Deucher Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/575885fd440c2b13c3f19ddf44360cfbbff35f50.1464685538.git.lukas@wunner.de

vga_switcheroo: Add support for switching only the DDC

2016-02-09T10:21:07+00:00

Originally by Seth Forshee , 2012-10-04: During graphics driver initialization it's useful to be able to mux only the DDC to the inactive client in order to read the EDID. Add a switch_ddc callback to allow capable handlers to provide this functionality, and add vga_switcheroo_switch_ddc() to allow DRM to mux only the DDC. Modified by Dave Airlie , 2012-12-22: I can't figure out why I didn't like this, but I rewrote this [...] to lock/unlock the ddc lines [...]. I think I'd prefer something like that otherwise the interface got really ugly. Modified by Lukas Wunner , 2015-04 - 2015-10: Change semantics of ->switch_ddc handler callback to return previous DDC owner. Original version tried to determine previous DDC owner with find_active_client() but this fails if the inactive client registers before the active client. Don't lock vgasr_mutex in _lock_ddc() / _unlock_ddc(), it can cause deadlocks because (a) during switch (with vgasr_mutex already held), GPU is woken and probes its outputs, tries to re-acquire vgasr_mutex to lock DDC lines; (b) Likewise during switch, GPU is suspended and calls cancel_delayed_work_sync() to stop output polling, if poll task is running at this moment we may wait forever for it to finish. Instead, lock mux_hw_lock when unregistering the handler because the only reason why we'd want to lock vgasr_mutex in _lock_ddc() / _unlock_ddc() is to block the handler from disappearing while DDC lines are switched. Also acquire mux_hw_lock in stage2 to avoid race condition where reading the EDID and switching happens simultaneously. Likewise on MIGD / MDIS commands and on runtime suspend. v2.1: Overhaul locking, squash commits (Daniel Vetter) v2.2: Readability improvements (Thierry Reding) v2.3: Overhaul locking once more v2.4: Retain semantics of ->switchto handler callback to switch all pins, including DDC (Daniel Vetter) v5: Rename ddc_lock to mux_hw_lock: Since we acquire this both when calling ->switch_ddc and ->switchto, it protects not just access to the DDC lines but to the mux in general. This is in line with the DRM convention to use low-level locks to avoid concurrent hw access (e.g. i2c, dp_aux) which are often called hw_lock (Daniel Vetter) Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Tested-by: Lukas Wunner [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"] Cc: Seth Forshee Cc: Dave Airlie Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/e81ae9722b84c5ed591805fee3ea6dbf5dc6c4b3.1452525860.git.lukas@wunner.de

vga_switcheroo: Add handler flags infrastructure

2016-02-09T10:21:07+00:00

Allow handlers to declare their capabilities and allow clients to obtain that information. So far we have these use cases: * If the handler is able to switch DDC separately, clients need to probe EDID with drm_get_edid_switcheroo(). We should allow them to detect a capable handler to ensure this function only gets called when needed. * Likewise if the handler is unable to switch AUX separately, the active client needs to communicate link training parameters to the inactive client, which may then skip the AUX handshake and set up its output with these pre-calibrated values (DisplayPort specification v1.1a, section 2.5.3.3). Clients need a way to recognize such a situation. The flags for the radeon_atpx_handler and amdgpu_atpx_handler are initially set to 0, this can later on be amended with handler_flags |= VGA_SWITCHEROO_CAN_SWITCH_DDC; when a ->switch_ddc callback is added. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Tested-by: Lukas Wunner [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"] Signed-off-by: Lukas Wunner Reviewed-by: Darren Hart Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/2b0d93ed6e511ca09e95e45e0b35627f330fabce.1452525860.git.lukas@wunner.de

Merge tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2016-01-21T03:06:49+00:00

Pull more power management and ACPI updates from Rafael Wysocki: "This includes fixes on top of the previous batch of PM+ACPI updates and some new material as well. From the new material perspective the most significant are the driver core changes that should allow USB devices to stay suspended over system suspend/resume cycles if they have been runtime-suspended already beforehand. Apart from that, ACPICA is updated to upstream revision 20160108 (cosmetic mostly, but including one fixup on top of the previous ACPICA update) and there are some devfreq updates the didn't make it before (due to timing). A few recent regressions are fixed, most importantly in the cpuidle menu governor and in the ACPI backlight driver and some x86 platform drivers depending on it. Some more bugs are fixed and cleanups are made on top of that. Specifics: - Modify the driver core and the USB subsystem to allow USB devices to stay suspended over system suspend/resume cycles if they have been runtime-suspended already beforehand and fix some bugs on top of these changes (Tomeu Vizoso, Rafael Wysocki). - Update ACPICA to upstream revision 20160108, including updates of the ACPICA's copyright notices, a code fixup resulting from a regression fix that was necessary in the upstream code only (the regression fixed by it has never been present in Linux) and a compiler warning fix (Bob Moore, Lv Zheng). - Fix a recent regression in the cpuidle menu governor that broke it on practically all architectures other than x86 and make a couple of optimizations on top of that fix (Rafael Wysocki). - Clean up the selection of cpuidle governors depending on whether or not the kernel is configured for tickless systems (Jean Delvare). - Revert a recent commit that introduced a regression in the ACPI backlight driver, address the problem it attempted to fix in a different way and revert one more cosmetic change depending on the problematic commit (Hans de Goede). - Add two more ACPI backlight quirks (Hans de Goede). - Fix a few minor problems in the core devfreq code, clean it up a bit and update the MAINTAINERS information related to it (Chanwoo Choi, MyungJoo Ham). - Improve an error message in the ACPI fan driver (Andy Lutomirski). - Fix a recent build regression in the cpupower tool (Shreyas Prabhu)" * tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (32 commits) cpuidle: menu: Avoid pointless checks in menu_select() sched / idle: Drop default_idle_call() fallback from call_cpuidle() cpupower: Fix build error in cpufreq-info cpuidle: Don't enable all governors by default cpuidle: Default to ladder governor on ticking systems time: nohz: Expose tick_nohz_enabled ACPICA: Update version to 20160108 ACPICA: Silence a -Wbad-function-cast warning when acpi_uintptr_t is 'uintptr_t' ACPICA: Additional 2016 copyright changes ACPICA: Reduce regression fix divergence from upstream ACPICA ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Satellite R830 ACPI / video: Revert "thinkpad_acpi: Use acpi_video_handles_brightness_key_presses()" ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit ACPI / video: Fix using an uninitialized mutex / list_head in acpi_video_handles_brightness_key_presses() ACPI / video: Revert "ACPI / video: driver must be registered before checking for keypresses" ACPI / fan: Improve acpi_device_update_power error message ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Portege R700 cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0 MAINTAINERS: Add devfreq-event entry MAINTAINERS: Add missing git repository and directory for devfreq ...

PM / Domains: add setter for dev.pm_domain

2016-01-08T00:12:06+00:00

Adds a function that sets the pointer to dev_pm_domain in struct device and that warns if the device has already finished probing. The reason why we want to enforce that is because in the general case that can cause problems and also that we can simplify code quite a bit if we can always assume that. This patch also changes all current code that directly sets the dev.pm_domain pointer. Signed-off-by: Tomeu Vizoso Reviewed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki

vga_switcheroo: Prettify documentation

2016-01-04T07:11:49+00:00

Fix indentation of vga_switcheroo sections in gpu.tmpl. Change section type of API documentation from "chapter" to "sect1" so that the individual functions no longer clutter up the ToC. Group together under a new "API" chapter. Fix wording "heretoforth" -> "henceforth". Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter

vga_switcheroo: Drop client power state VGA_SWITCHEROO_INIT

2015-11-05T01:07:36+00:00

hda_intel.c:azx_probe() defers initialization of an audio controller on the discrete GPU if the GPU is powered off. The power state of the GPU is determined by calling vga_switcheroo_get_client_state(). vga_switcheroo_get_client_state() returns VGA_SWITCHEROO_INIT if vga_switcheroo is not enabled, i.e. if no second GPU or no handler has registered. This can go wrong in the following scenario: - Driver for the integrated GPU is not loaded. - Driver for the discrete GPU registers with vga_switcheroo, uses driver power control to power down the GPU, handler cuts power to the GPU. - Driver for the audio controller gets loaded after the GPU was powered down, calls vga_switcheroo_get_client_state() which returns VGA_SWITCHEROO_INIT instead of VGA_SWITCHEROO_OFF. - Consequence: azx_probe() tries to initialize the audio controller even though the GPU is powered down. The power state VGA_SWITCHEROO_INIT was introduced by c8e9cf7bb240 ("vga_switcheroo: Add a helper function to get the client state"). It is not apparent what its benefit might be. The idea seems to be to initialize the audio controller even if the power state is VGA_SWITCHEROO_OFF (were vga_switcheroo enabled), but as shown above this can fail. Drop VGA_SWITCHEROO_INIT to solve this. Acked-by: Takashi Iwai Signed-off-by: Lukas Wunner Signed-off-by: Dave Airlie

vga_switcheroo: Constify vga_switcheroo_handler

2015-10-20T18:19:29+00:00

vga_switcheroo_client_ops has always been declared const since its introduction with 26ec685ff9d9 ("vga_switcheroo: Introduce struct vga_switcheroo_client_ops"). Do so for vga_switcheroo_handler as well. drivers/gpu/drm/amd/amdgpu/amdgpu.ko: 6 .rodata 00009888 - 19 .data 00001f00 + 19 .data 00001ee0 drivers/gpu/drm/nouveau/nouveau.ko: 6 .rodata 000460b8 17 .data 00018fe0 drivers/gpu/drm/radeon/radeon.ko: - 7 .rodata 00030944 + 7 .rodata 00030964 - 21 .data 0000d6a0 + 21 .data 0000d678 drivers/platform/x86/apple-gmux.ko: - 7 .rodata 00000140 + 7 .rodata 00000160 - 11 .data 000000e0 + 11 .data 000000b8 Cc: Ben Skeggs Cc: Darren Hart Cc: Alex Deucher Signed-off-by: Lukas Wunner Reviewed-by: Christian König . Signed-off-by: Daniel Vetter