diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/gpu/drm-kms-helpers.rst | 211 | ||||
| -rw-r--r-- | Documentation/gpu/drm-kms.rst | 270 | ||||
| -rw-r--r-- | Documentation/gpu/drm-mm.rst | 58 | ||||
| -rw-r--r-- | Documentation/gpu/drm-uapi.rst | 3 | ||||
| -rw-r--r-- | Documentation/gpu/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/gpu/vga-switcheroo.rst | 2 | ||||
| -rw-r--r-- | Documentation/gpu/vgaarbiter.rst (renamed from Documentation/vgaarbiter.txt) | 161 |
7 files changed, 276 insertions, 430 deletions
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst index 0b302fedf1af..59fa3c11efab 100644 --- a/Documentation/gpu/drm-kms-helpers.rst +++ b/Documentation/gpu/drm-kms-helpers.rst @@ -2,38 +2,45 @@ Mode Setting Helper Functions ============================= -The plane, CRTC, encoder and connector functions provided by the drivers -implement the DRM API. They're called by the DRM core and ioctl handlers -to handle device state changes and configuration request. As -implementing those functions often requires logic not specific to -drivers, mid-layer helper functions are available to avoid duplicating -boilerplate code. - -The DRM core contains one mid-layer implementation. The mid-layer -provides implementations of several plane, CRTC, encoder and connector -functions (called from the top of the mid-layer) that pre-process -requests and call lower-level functions provided by the driver (at the -bottom of the mid-layer). For instance, the -:c:func:`drm_crtc_helper_set_config()` function can be used to -fill the :c:type:`struct drm_crtc_funcs <drm_crtc_funcs>` -set_config field. When called, it will split the set_config operation -in smaller, simpler operations and call the driver to handle them. - -To use the mid-layer, drivers call -:c:func:`drm_crtc_helper_add()`, -:c:func:`drm_encoder_helper_add()` and -:c:func:`drm_connector_helper_add()` functions to install their -mid-layer bottom operations handlers, and fill the :c:type:`struct -drm_crtc_funcs <drm_crtc_funcs>`, :c:type:`struct -drm_encoder_funcs <drm_encoder_funcs>` and :c:type:`struct -drm_connector_funcs <drm_connector_funcs>` structures with -pointers to the mid-layer top API functions. Installing the mid-layer -bottom operation handlers is best done right after registering the -corresponding KMS object. - -The mid-layer is not split between CRTC, encoder and connector -operations. To use it, a driver must provide bottom functions for all of -the three KMS entities. +The DRM subsystem aims for a strong separation between core code and helper +libraries. Core code takes care of general setup and teardown and decoding +userspace requests to kernel internal objects. Everything else is handled by a +large set of helper libraries, which can be combined freely to pick and choose +for each driver what fits, and avoid shared code where special behaviour is +needed. + +This distinction between core code and helpers is especially strong in the +modesetting code, where there's a shared userspace ABI for all drivers. This is +in contrast to the render side, where pretty much everything (with very few +exceptions) can be considered optional helper code. + +There are a few areas these helpers can grouped into: + +* Helpers to implement modesetting. The important ones here are the atomic + helpers. Old drivers still often use the legacy CRTC helpers. They both share + the same set of common helper vtables. For really simple drivers (anything + that would have been a great fit in the deprecated fbdev subsystem) there's + also the simple display pipe helpers. + +* There's a big pile of helpers for handling outputs. First the generic bridge + helpers for handling encoder and transcoder IP blocks. Second the panel helpers + for handling panel-related information and logic. Plus then a big set of + helpers for the various sink standards (DisplayPort, HDMI, MIPI DSI). Finally + there's also generic helpers for handling output probing, and for dealing with + EDIDs. + +* The last group of helpers concerns itself with the frontend side of a display + pipeline: Planes, handling rectangles for visibility checking and scissoring, + flip queues and assorted bits. + +Modeset Helper Reference for Common Vtables +=========================================== + +.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h + :internal: + +.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h + :doc: overview Atomic Modeset Helper Functions Reference ========================================= @@ -62,33 +69,27 @@ Atomic State Reset and Initialization .. kernel-doc:: drivers/gpu/drm/drm_atomic_helper.c :export: -Modeset Helper Reference for Common Vtables -=========================================== - -.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h - :internal: - -.. kernel-doc:: include/drm/drm_modeset_helper_vtables.h - :doc: overview - Legacy CRTC/Modeset Helper Functions Reference ============================================== .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c - :export: + :doc: overview .. kernel-doc:: drivers/gpu/drm/drm_crtc_helper.c - :doc: overview + :export: -Output Probing Helper Functions Reference -========================================= +Simple KMS Helper Reference +=========================== -.. kernel-doc:: drivers/gpu/drm/drm_probe_helper.c - :doc: output probing helper overview +.. kernel-doc:: include/drm/drm_simple_kms_helper.h + :internal: -.. kernel-doc:: drivers/gpu/drm/drm_probe_helper.c +.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c :export: +.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c + :doc: overview + fbdev Helper Functions Reference ================================ @@ -110,6 +111,36 @@ Framebuffer CMA Helper Functions Reference .. kernel-doc:: drivers/gpu/drm/drm_fb_cma_helper.c :export: +Bridges +======= + +Overview +-------- + +.. kernel-doc:: drivers/gpu/drm/drm_bridge.c + :doc: overview + +Default bridge callback sequence +-------------------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_bridge.c + :doc: bridge callbacks + +.. kernel-doc:: drivers/gpu/drm/drm_bridge.c + :export: + +Panel Helper Reference +====================== + +.. kernel-doc:: include/drm/drm_panel.h + :internal: + +.. kernel-doc:: drivers/gpu/drm/drm_panel.c + :export: + +.. kernel-doc:: drivers/gpu/drm/drm_panel.c + :doc: drm panel + Display Port Helper Functions Reference ======================================= @@ -158,6 +189,15 @@ MIPI DSI Helper Functions Reference .. kernel-doc:: drivers/gpu/drm/drm_mipi_dsi.c :export: +Output Probing Helper Functions Reference +========================================= + +.. kernel-doc:: drivers/gpu/drm/drm_probe_helper.c + :doc: output probing helper overview + +.. kernel-doc:: drivers/gpu/drm/drm_probe_helper.c + :export: + EDID Helper Functions Reference =============================== @@ -176,18 +216,6 @@ Rectangle Utilities Reference .. kernel-doc:: drivers/gpu/drm/drm_rect.c :export: -Flip-work Helper Reference -========================== - -.. kernel-doc:: include/drm/drm_flip_work.h - :doc: flip utils - -.. kernel-doc:: include/drm/drm_flip_work.h - :internal: - -.. kernel-doc:: drivers/gpu/drm/drm_flip_work.c - :export: - HDMI Infoframes Helper Reference ================================ @@ -202,59 +230,40 @@ libraries and hence is also included here. .. kernel-doc:: drivers/video/hdmi.c :export: -Plane Helper Reference -====================== - -.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c - :export: - -.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c - :doc: overview +Flip-work Helper Reference +========================== -Tile group ----------- +.. kernel-doc:: include/drm/drm_flip_work.h + :doc: flip utils -.. kernel-doc:: drivers/gpu/drm/drm_crtc.c - :doc: Tile group +.. kernel-doc:: include/drm/drm_flip_work.h + :internal: -Bridges -======= +.. kernel-doc:: drivers/gpu/drm/drm_flip_work.c + :export: -Overview --------- +Plane Helper Reference +====================== -.. kernel-doc:: drivers/gpu/drm/drm_bridge.c +.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c :doc: overview -Default bridge callback sequence --------------------------------- - -.. kernel-doc:: drivers/gpu/drm/drm_bridge.c - :doc: bridge callbacks - -.. kernel-doc:: drivers/gpu/drm/drm_bridge.c +.. kernel-doc:: drivers/gpu/drm/drm_plane_helper.c :export: -Panel Helper Reference -====================== - -.. kernel-doc:: include/drm/drm_panel.h - :internal: +Tile group +========== -.. kernel-doc:: drivers/gpu/drm/drm_panel.c - :export: +# FIXME: This should probably be moved into a property documentation section -.. kernel-doc:: drivers/gpu/drm/drm_panel.c - :doc: drm panel +.. kernel-doc:: drivers/gpu/drm/drm_crtc.c + :doc: Tile group -Simple KMS Helper Reference -=========================== +Auxiliary Modeset Helpers +========================= -.. kernel-doc:: include/drm/drm_simple_kms_helper.h - :internal: +.. kernel-doc:: drivers/gpu/drm/drm_modeset_helper.c + :doc: aux kms helpers -.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c +.. kernel-doc:: drivers/gpu/drm/drm_modeset_helper.c :export: - -.. kernel-doc:: drivers/gpu/drm/drm_simple_kms_helper.c - :doc: overview diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index 8dfa4b214b96..fa948b4e029b 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -2,9 +2,6 @@ Kernel Mode Setting (KMS) ========================= -Mode Setting -============ - Drivers must initialize the mode setting core by calling :c:func:`drm_mode_config_init()` on the DRM device. The function initializes the :c:type:`struct drm_device <drm_device>` @@ -18,60 +15,50 @@ be setup by initializing the following fields. - struct drm_mode_config_funcs \*funcs; Mode setting functions. -Display Modes Function Reference --------------------------------- +KMS Data Structures +=================== -.. kernel-doc:: include/drm/drm_modes.h +.. kernel-doc:: include/drm/drm_crtc.h :internal: -.. kernel-doc:: drivers/gpu/drm/drm_modes.c +KMS API Functions +================= + +.. kernel-doc:: drivers/gpu/drm/drm_crtc.c :export: Atomic Mode Setting Function Reference --------------------------------------- +====================================== .. kernel-doc:: drivers/gpu/drm/drm_atomic.c :export: -.. kernel-doc:: drivers/gpu/drm/drm_atomic.c +.. kernel-doc:: include/drm/drm_atomic.h :internal: Frame Buffer Abstraction ------------------------- - -Frame buffers are abstract memory objects that provide a source of -pixels to scanout to a CRTC. Applications explicitly request the -creation of frame buffers through the DRM_IOCTL_MODE_ADDFB(2) ioctls -and receive an opaque handle that can be passed to the KMS CRTC control, -plane configuration and page flip functions. - -Frame buffers rely on the underneath memory manager for low-level memory -operations. When creating a frame buffer applications pass a memory -handle (or a list of memory handles for multi-planar formats) through -the ``drm_mode_fb_cmd2`` argument. For drivers using GEM as their -userspace buffer management interface this would be a GEM handle. -Drivers are however free to use their own backing storage object -handles, e.g. vmwgfx directly exposes special TTM handles to userspace -and so expects TTM handles in the create ioctl and not GEM handles. - -The lifetime of a drm framebuffer is controlled with a reference count, -drivers can grab additional references with -:c:func:`drm_framebuffer_reference()`and drop them again with -:c:func:`drm_framebuffer_unreference()`. For driver-private -framebuffers for which the last reference is never dropped (e.g. for the -fbdev framebuffer when the struct :c:type:`struct drm_framebuffer -<drm_framebuffer>` is embedded into the fbdev helper struct) -drivers can manually clean up a framebuffer at module unload time with -:c:func:`drm_framebuffer_unregister_private()`. +======================== + +.. kernel-doc:: drivers/gpu/drm/drm_framebuffer.c + :doc: overview + +Frame Buffer Functions Reference +-------------------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_framebuffer.c + :export: + +.. kernel-doc:: include/drm/drm_framebuffer.h + :internal: DRM Format Handling -------------------- +=================== .. kernel-doc:: drivers/gpu/drm/drm_fourcc.c :export: Dumb Buffer Objects -------------------- +=================== The KMS API doesn't standardize backing storage object creation and leaves it to driver-specific ioctls. Furthermore actually creating a @@ -114,14 +101,29 @@ Note that dumb objects may not be used for gpu acceleration, as has been attempted on some ARM embedded platforms. Such drivers really must have a hardware-specific ioctl to allocate suitable buffer objects. -Output Polling --------------- +Display Modes Function Reference +================================ + +.. kernel-doc:: include/drm/drm_modes.h + :internal: + +.. kernel-doc:: drivers/gpu/drm/drm_modes.c + :export: + +Connector Abstraction +===================== + +.. kernel-doc:: drivers/gpu/drm/drm_connector.c + :doc: overview -void (\*output_poll_changed)(struct drm_device \*dev); -This operation notifies the driver that the status of one or more -connectors has changed. Drivers that use the fb helper can just call the -:c:func:`drm_fb_helper_hotplug_event()` function to handle this -operation. +Connector Functions Reference +----------------------------- + +.. kernel-doc:: include/drm/drm_connector.h + :internal: + +.. kernel-doc:: drivers/gpu/drm/drm_connector.c + :export: KMS Initialization and Cleanup ============================== @@ -236,166 +238,6 @@ encoders unattached at initialization time. Applications (or the fbdev compatibility layer when implemented) are responsible for attaching the encoders they want to use to a CRTC. -Connectors (:c:type:`struct drm_connector <drm_connector>`) ------------------------------------------------------------ - -A connector is the final destination for pixel data on a device, and -usually connects directly to an external display device like a monitor -or laptop panel. A connector can only be attached to one encoder at a -time. The connector is also the structure where information about the -attached display is kept, so it contains fields for display data, EDID -data, DPMS & connection status, and information about modes supported on -the attached displays. - -Connector Initialization -~~~~~~~~~~~~~~~~~~~~~~~~ - -Finally a KMS driver must create, initialize, register and attach at -least one :c:type:`struct drm_connector <drm_connector>` -instance. The instance is created as other KMS objects and initialized -by setting the following fields. - -interlace_allowed - Whether the connector can handle interlaced modes. - -doublescan_allowed - Whether the connector can handle doublescan. - -display_info - Display information is filled from EDID information when a display - is detected. For non hot-pluggable displays such as flat panels in - embedded systems, the driver should initialize the - display_info.width_mm and display_info.height_mm fields with the - physical size of the display. - -polled - Connector polling mode, a combination of - - DRM_CONNECTOR_POLL_HPD - The connector generates hotplug events and doesn't need to be - periodically polled. The CONNECT and DISCONNECT flags must not - be set together with the HPD flag. - - DRM_CONNECTOR_POLL_CONNECT - Periodically poll the connector for connection. - - DRM_CONNECTOR_POLL_DISCONNECT - Periodically poll the connector for disconnection. - - Set to 0 for connectors that don't support connection status - discovery. - -The connector is then registered with a call to -:c:func:`drm_connector_init()` with a pointer to the connector -functions and a connector type, and exposed through sysfs with a call to -:c:func:`drm_connector_register()`. - -Supported connector types are - -- DRM_MODE_CONNECTOR_VGA -- DRM_MODE_CONNECTOR_DVII -- DRM_MODE_CONNECTOR_DVID -- DRM_MODE_CONNECTOR_DVIA -- DRM_MODE_CONNECTOR_Composite -- DRM_MODE_CONNECTOR_SVIDEO -- DRM_MODE_CONNECTOR_LVDS -- DRM_MODE_CONNECTOR_Component -- DRM_MODE_CONNECTOR_9PinDIN -- DRM_MODE_CONNECTOR_DisplayPort -- DRM_MODE_CONNECTOR_HDMIA -- DRM_MODE_CONNECTOR_HDMIB -- DRM_MODE_CONNECTOR_TV -- DRM_MODE_CONNECTOR_eDP -- DRM_MODE_CONNECTOR_VIRTUAL - -Connectors must be attached to an encoder to be used. For devices that -map connectors to encoders 1:1, the connector should be attached at -initialization time with a call to -:c:func:`drm_mode_connector_attach_encoder()`. The driver must -also set the :c:type:`struct drm_connector <drm_connector>` -encoder field to point to the attached encoder. - -Finally, drivers must initialize the connectors state change detection -with a call to :c:func:`drm_kms_helper_poll_init()`. If at least -one connector is pollable but can't generate hotplug interrupts -(indicated by the DRM_CONNECTOR_POLL_CONNECT and -DRM_CONNECTOR_POLL_DISCONNECT connector flags), a delayed work will -automatically be queued to periodically poll for changes. Connectors -that can generate hotplug interrupts must be marked with the -DRM_CONNECTOR_POLL_HPD flag instead, and their interrupt handler must -call :c:func:`drm_helper_hpd_irq_event()`. The function will -queue a delayed work to check the state of all connectors, but no -periodic polling will be done. - -Connector Operations -~~~~~~~~~~~~~~~~~~~~ - - **Note** - - Unless otherwise state, all operations are mandatory. - -DPMS -'''' - -void (\*dpms)(struct drm_connector \*connector, int mode); -The DPMS operation sets the power state of a connector. The mode -argument is one of - -- DRM_MODE_DPMS_ON - -- DRM_MODE_DPMS_STANDBY - -- DRM_MODE_DPMS_SUSPEND - -- DRM_MODE_DPMS_OFF - -In all but DPMS_ON mode the encoder to which the connector is attached -should put the display in low-power mode by driving its signals -appropriately. If more than one connector is attached to the encoder -care should be taken not to change the power state of other displays as -a side effect. Low-power mode should be propagated to the encoders and -CRTCs when all related connectors are put in low-power mode. - -Modes -''''' - -int (\*fill_modes)(struct drm_connector \*connector, uint32_t -max_width, uint32_t max_height); -Fill the mode list with all supported modes for the connector. If the -``max_width`` and ``max_height`` arguments are non-zero, the -implementation must ignore all modes wider than ``max_width`` or higher -than ``max_height``. - -The connector must also fill in this operation its display_info -width_mm and height_mm fields with the connected display physical size -in millimeters. The fields should be set to 0 if the value isn't known -or is not applicable (for instance for projector devices). - -Connection Status -''''''''''''''''' - -The connection status is updated through polling or hotplug events when -supported (see ?). The status value is reported to userspace through -ioctls and must not be used inside the driver, as it only gets -initialized by a call to :c:func:`drm_mode_getconnector()` from -userspace. - -enum drm_connector_status (\*detect)(struct drm_connector -\*connector, bool force); -Check to see if anything is attached to the connector. The ``force`` -parameter is set to false whilst polling or to true when checking the -connector due to user request. ``force`` can be used by the driver to -avoid expensive, destructive operations during automated probing. - -Return connector_status_connected if something is connected to the -connector, connector_status_disconnected if nothing is connected and -connector_status_unknown if the connection state isn't known. - -Drivers should only return connector_status_connected if the -connection status has really been probed as connected. Connectors that -can't detect the connection status, or failed connection status probes, -should return connector_status_unknown. - Cleanup ------- @@ -463,20 +305,8 @@ created for fetching EDID data and performing monitor detection. Once the process is complete, the new connector is registered with sysfs to make its properties available to applications. -KMS API Functions ------------------ - -.. kernel-doc:: drivers/gpu/drm/drm_crtc.c - :export: - -KMS Data Structures -------------------- - -.. kernel-doc:: include/drm/drm_crtc.h - :internal: - KMS Locking ------------ +=========== .. kernel-doc:: drivers/gpu/drm/drm_modeset_lock.c :doc: kms locking @@ -575,6 +405,12 @@ connector and plane objects by calling the pointer to the target object, a pointer to the previously created property and an initial instance value. +Blending and Z-Position properties +---------------------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_blend.c + :export: + Existing KMS Properties ----------------------- diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index 59f9822fecd0..bca808535dfd 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -26,12 +26,12 @@ TTM, but has no video RAM management capabilities and is thus limited to UMA devices. The Translation Table Manager (TTM) ------------------------------------ +=================================== TTM design background and information belongs here. TTM initialization -~~~~~~~~~~~~~~~~~~ +------------------ **Warning** @@ -77,7 +77,7 @@ object, ttm_global_item_ref() is used to create an initial reference count for the TTM, which will call your initialization function. The Graphics Execution Manager (GEM) ------------------------------------- +==================================== The GEM design approach has resulted in a memory manager that doesn't provide full coverage of all (or even all common) use cases in its @@ -114,7 +114,7 @@ read & write, mapping, and domain ownership transfers are left to driver-specific ioctls. GEM Initialization -~~~~~~~~~~~~~~~~~~ +------------------ Drivers that use GEM must set the DRIVER_GEM bit in the struct :c:type:`struct drm_driver <drm_driver>` driver_features @@ -132,7 +132,7 @@ typically not managed by GEM, and must be initialized separately into its own DRM MM object. GEM Objects Creation -~~~~~~~~~~~~~~~~~~~~ +-------------------- GEM splits creation of GEM objects and allocation of the memory that backs them in two distinct operations. @@ -173,7 +173,7 @@ a call to :c:func:`drm_gem_private_object_init()` instead of must be managed by drivers. GEM Objects Lifetime -~~~~~~~~~~~~~~~~~~~~ +-------------------- All GEM objects are reference-counted by the GEM core. References can be acquired and release by :c:func:`calling @@ -196,7 +196,7 @@ resources created by the GEM core, which need to be released with :c:func:`drm_gem_object_release()`. GEM Objects Naming -~~~~~~~~~~~~~~~~~~ +------------------ Communication between userspace and the kernel refers to GEM objects using local handles, global names or, more recently, file descriptors. @@ -245,7 +245,7 @@ Furthermore PRIME also allows cross-device buffer sharing since it is based on dma-bufs. GEM Objects Mapping -~~~~~~~~~~~~~~~~~~~ +------------------- Because mapping operations are fairly heavyweight GEM favours read/write-like access to buffers, implemented through driver-specific @@ -304,7 +304,7 @@ Drivers that want to map the GEM object upfront instead of handling page faults can implement their own mmap file operation handler. Memory Coherency -~~~~~~~~~~~~~~~~ +---------------- When mapped to the device or used in a command buffer, backing pages for an object are flushed to memory and marked write combined so as to be @@ -320,7 +320,7 @@ blocks the client and waits for rendering to complete before performing any necessary flushing operations). Command Execution -~~~~~~~~~~~~~~~~~ +----------------- Perhaps the most important GEM function for GPU devices is providing a command execution interface to clients. Client programs construct @@ -348,8 +348,20 @@ GEM Function Reference .. kernel-doc:: include/drm/drm_gem.h :internal: +GEM CMA Helper Functions Reference +---------------------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c + :doc: cma helpers + +.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c + :export: + +.. kernel-doc:: include/drm/drm_gem_cma_helper.h + :internal: + VMA Offset Manager ------------------- +================== .. kernel-doc:: drivers/gpu/drm/drm_vma_manager.c :doc: vma offset manager @@ -361,14 +373,14 @@ VMA Offset Manager :internal: PRIME Buffer Sharing --------------------- +==================== PRIME is the cross device buffer sharing framework in drm, originally created for the OPTIMUS range of multi-gpu platforms. To userspace PRIME buffers are dma-buf based file descriptors. Overview and Driver Interface -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +----------------------------- Similar to GEM global names, PRIME file descriptors are also used to share buffer objects across processes. They offer additional security: @@ -406,7 +418,7 @@ struct drm_gem_object \*obj, int flags); struct drm_gem_object \* support PRIME. PRIME Helper Functions -~~~~~~~~~~~~~~~~~~~~~~ +---------------------- .. kernel-doc:: drivers/gpu/drm/drm_prime.c :doc: PRIME Helpers @@ -418,16 +430,16 @@ PRIME Function References :export: DRM MM Range Allocator ----------------------- +====================== Overview -~~~~~~~~ +-------- .. kernel-doc:: drivers/gpu/drm/drm_mm.c :doc: Overview LRU Scan/Eviction Support -~~~~~~~~~~~~~~~~~~~~~~~~~ +------------------------- .. kernel-doc:: drivers/gpu/drm/drm_mm.c :doc: lru scan roaster @@ -440,15 +452,3 @@ DRM MM Range Allocator Function References .. kernel-doc:: include/drm/drm_mm.h :internal: - -CMA Helper Functions Reference ------------------------------- - -.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c - :doc: cma helpers - -.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c - :export: - -.. kernel-doc:: include/drm/drm_gem_cma_helper.h - :internal: diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index 536bf3eaadd4..94876938aef3 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -33,6 +33,9 @@ Primary Nodes, DRM Master and Authentication .. kernel-doc:: include/drm/drm_auth.h :internal: +Open-Source Userspace Requirements +================================== + Render nodes ============ diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst index fcac0fa72056..ba92f45abb76 100644 --- a/Documentation/gpu/index.rst +++ b/Documentation/gpu/index.rst @@ -12,3 +12,4 @@ Linux GPU Driver Developer's Guide drm-uapi i915 vga-switcheroo + vgaarbiter diff --git a/Documentation/gpu/vga-switcheroo.rst b/Documentation/gpu/vga-switcheroo.rst index cbbdb994f1dd..463a74fc40d1 100644 --- a/Documentation/gpu/vga-switcheroo.rst +++ b/Documentation/gpu/vga-switcheroo.rst @@ -1,5 +1,3 @@ -.. _vga_switcheroo: - ============== VGA Switcheroo ============== diff --git a/Documentation/vgaarbiter.txt b/Documentation/gpu/vgaarbiter.rst index 014423e2824c..0b41b051d021 100644 --- a/Documentation/vgaarbiter.txt +++ b/Documentation/gpu/vgaarbiter.rst @@ -1,4 +1,4 @@ - +=========== VGA Arbiter =========== @@ -19,21 +19,8 @@ control bus resources. Therefore an arbitration scheme outside of the X server is needed to control the sharing of these resources. This document introduces the operation of the VGA arbiter implemented for the Linux kernel. ----------------------------------------------------------------------------- - -I. Details and Theory of Operation - I.1 vgaarb - I.2 libpciaccess - I.3 xf86VGAArbiter (X server implementation) -II. Credits -III.References - - -I. Details and Theory of Operation -================================== - -I.1 vgaarb ----------- +vgaarb kernel/userspace ABI +--------------------------- The vgaarb is a module of the Linux Kernel. When it is initially loaded, it scans all PCI devices and adds the VGA ones inside the arbitration. The @@ -44,42 +31,52 @@ explicitly tell it by calling vga_set_legacy_decoding(). The kernel exports a char device interface (/dev/vga_arbiter) to the clients, which has the following semantics: - open : open user instance of the arbiter. By default, it's attached to - the default VGA device of the system. - - close : close user instance. Release locks made by the user - - read : return a string indicating the status of the target like: - - "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" - - An IO state string is of the form {io,mem,io+mem,none}, mc and - ic are respectively mem and io lock counts (for debugging/ - diagnostic only). "decodes" indicate what the card currently - decodes, "owns" indicates what is currently enabled on it, and - "locks" indicates what is locked by this card. If the card is - unplugged, we get "invalid" then for card_ID and an -ENODEV - error is returned for any command until a new card is targeted. - - - write : write a command to the arbiter. List of commands: - - target <card_ID> : switch target to card <card_ID> (see below) - lock <io_state> : acquires locks on target ("none" is an invalid io_state) - trylock <io_state> : non-blocking acquire locks on target (returns EBUSY if - unsuccessful) - unlock <io_state> : release locks on target - unlock all : release all locks on target held by this user (not - implemented yet) - decodes <io_state> : set the legacy decoding attributes for the card - - poll : event if something changes on any card (not just the - target) - - card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" - to go back to the system default card (TODO: not implemented yet). Currently, - only PCI is supported as a prefix, but the userland API may support other bus - types in the future, even if the current kernel implementation doesn't. +open + Opens a user instance of the arbiter. By default, it's attached to the + default VGA device of the system. + +close + Close a user instance. Release locks made by the user + +read + Return a string indicating the status of the target like: + + "<card_ID>,decodes=<io_state>,owns=<io_state>,locks=<io_state> (ic,mc)" + + An IO state string is of the form {io,mem,io+mem,none}, mc and + ic are respectively mem and io lock counts (for debugging/ + diagnostic only). "decodes" indicate what the card currently + decodes, "owns" indicates what is currently enabled on it, and + "locks" indicates what is locked by this card. If the card is + unplugged, we get "invalid" then for card_ID and an -ENODEV + error is returned for any command until a new card is targeted. + + +write + Write a command to the arbiter. List of commands: + + target <card_ID> + switch target to card <card_ID> (see below) + lock <io_state> + acquires locks on target ("none" is an invalid io_state) + trylock <io_state> + non-blocking acquire locks on target (returns EBUSY if + unsuccessful) + unlock <io_state> + release locks on target + unlock all + release all locks on target held by this user (not implemented + yet) + decodes <io_state> + set the legacy decoding attributes for the card + + poll + event if something changes on any card (not just the target) + + card_ID is of the form "PCI:domain:bus:dev.fn". It can be set to "default" + to go back to the system default card (TODO: not implemented yet). Currently, + only PCI is supported as a prefix, but the userland API may support other bus + types in the future, even if the current kernel implementation doesn't. Note about locks: @@ -97,29 +94,35 @@ in the arbiter. There is also an in-kernel API of the arbiter in case DRM, vgacon, or other drivers want to use it. +In-kernel interface +------------------- + +.. kernel-doc:: include/linux/vgaarb.h + :internal: -I.2 libpciaccess ----------------- +.. kernel-doc:: drivers/gpu/vga/vgaarb.c + :export: + +libpciaccess +------------ To use the vga arbiter char device it was implemented an API inside the libpciaccess library. One field was added to struct pci_device (each device -on the system): +on the system):: /* the type of resource decoded by the device */ int vgaarb_rsrc; -Besides it, in pci_system were added: +Besides it, in pci_system were added:: int vgaarb_fd; int vga_count; struct pci_device *vga_target; struct pci_device *vga_default_dev; - The vga_count is used to track how many cards are being arbitrated, so for instance, if there is only one card, then it can completely escape arbitration. - These functions below acquire VGA resources for the given card and mark those resources as locked. If the resources requested are "normal" (and not legacy) resources, the arbiter will first check whether the card is doing legacy @@ -136,44 +139,44 @@ VGA memory and IO afaik). If the card already owns the resources, the function succeeds. vga_arb_trylock() will return (-EBUSY) instead of blocking. Nested calls are supported (a per-resource counter is maintained). +Set the target device of this client. :: -Set the target device of this client. int pci_device_vgaarb_set_target (struct pci_device *dev); - For instance, in x86 if two devices on the same bus want to lock different resources, both will succeed (lock). If devices are in different buses and -trying to lock different resources, only the first who tried succeeds. +trying to lock different resources, only the first who tried succeeds. :: + int pci_device_vgaarb_lock (void); int pci_device_vgaarb_trylock (void); -Unlock resources of device. +Unlock resources of device. :: + int pci_device_vgaarb_unlock (void); Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA Memory, both, or none. All cards default to both, the card driver (fbdev for example) should tell the arbiter if it has disabled legacy decoding, so the card can be left out of the arbitration process (and can be safe to take -interrupts at any time. +interrupts at any time. :: + int pci_device_vgaarb_decodes (int new_vgaarb_rsrc); -Connects to the arbiter device, allocates the struct - int pci_device_vgaarb_init (void); +Connects to the arbiter device, allocates the struct :: -Close the connection - void pci_device_vgaarb_fini (void); + int pci_device_vgaarb_init (void); +Close the connection :: -I.3 xf86VGAArbiter (X server implementation) --------------------------------------------- + void pci_device_vgaarb_fini (void); -(TODO) +xf86VGAArbiter (X server implementation) +---------------------------------------- X server basically wraps all the functions that touch VGA registers somehow. - -II. Credits -=========== +References +---------- Benjamin Herrenschmidt (IBM?) started this work when he discussed such design with the Xorg community in 2005 [1, 2]. In the end of 2007, Paulo Zanoni and @@ -182,11 +185,7 @@ enhancing the kernel code to adapt as a kernel module and also did the implementation of the user space side [3]. Now (2009) Tiago Vignatti and Dave Airlie finally put this work in shape and queued to Jesse Barnes' PCI tree. - -III. References -============== - -[0] http://cgit.freedesktop.org/xorg/xserver/commit/?id=4b42448a2388d40f257774fbffdccaea87bd0347 -[1] http://lists.freedesktop.org/archives/xorg/2005-March/006663.html -[2] http://lists.freedesktop.org/archives/xorg/2005-March/006745.html -[3] http://lists.freedesktop.org/archives/xorg/2007-October/029507.html +0) http://cgit.freedesktop.org/xorg/xserver/commit/?id=4b42448a2388d40f257774fbffdccaea87bd0347 +1) http://lists.freedesktop.org/archives/xorg/2005-March/006663.html +2) http://lists.freedesktop.org/archives/xorg/2005-March/006745.html +3) http://lists.freedesktop.org/archives/xorg/2007-October/029507.html |