diff options
Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/drivers.rst | 2 | ||||
| -rw-r--r-- | Documentation/gpu/i915.rst | 141 | ||||
| -rw-r--r-- | Documentation/gpu/kms-properties.csv | 1 | ||||
| -rw-r--r-- | Documentation/gpu/todo.rst | 18 | ||||
| -rw-r--r-- | Documentation/gpu/xen-front.rst | 31 |
5 files changed, 172 insertions, 21 deletions
diff --git a/Documentation/gpu/drivers.rst b/Documentation/gpu/drivers.rst index e8c84419a2a1..f982558fc25d 100644 --- a/Documentation/gpu/drivers.rst +++ b/Documentation/gpu/drivers.rst @@ -10,8 +10,10 @@ GPU Driver Documentation tegra tinydrm tve200 + v3d vc4 bridge/dw-hdmi + xen-front .. only:: subproject and html diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst index 41dc881b00dc..055df45596c1 100644 --- a/Documentation/gpu/i915.rst +++ b/Documentation/gpu/i915.rst @@ -58,6 +58,12 @@ Intel GVT-g Host Support(vGPU device model) .. kernel-doc:: drivers/gpu/drm/i915/intel_gvt.c :internal: +Workarounds +----------- + +.. kernel-doc:: drivers/gpu/drm/i915/intel_workarounds.c + :doc: Hardware workarounds + Display Hardware Handling ========================= @@ -249,6 +255,103 @@ Memory Management and Command Submission This sections covers all things related to the GEM implementation in the i915 driver. +Intel GPU Basics +---------------- + +An Intel GPU has multiple engines. There are several engine types. + +- RCS engine is for rendering 3D and performing compute, this is named + `I915_EXEC_RENDER` in user space. +- BCS is a blitting (copy) engine, this is named `I915_EXEC_BLT` in user + space. +- VCS is a video encode and decode engine, this is named `I915_EXEC_BSD` + in user space +- VECS is video enhancement engine, this is named `I915_EXEC_VEBOX` in user + space. +- The enumeration `I915_EXEC_DEFAULT` does not refer to specific engine; + instead it is to be used by user space to specify a default rendering + engine (for 3D) that may or may not be the same as RCS. + +The Intel GPU family is a family of integrated GPU's using Unified +Memory Access. For having the GPU "do work", user space will feed the +GPU batch buffers via one of the ioctls `DRM_IOCTL_I915_GEM_EXECBUFFER2` +or `DRM_IOCTL_I915_GEM_EXECBUFFER2_WR`. Most such batchbuffers will +instruct the GPU to perform work (for example rendering) and that work +needs memory from which to read and memory to which to write. All memory +is encapsulated within GEM buffer objects (usually created with the ioctl +`DRM_IOCTL_I915_GEM_CREATE`). An ioctl providing a batchbuffer for the GPU +to create will also list all GEM buffer objects that the batchbuffer reads +and/or writes. For implementation details of memory management see +`GEM BO Management Implementation Details`_. + +The i915 driver allows user space to create a context via the ioctl +`DRM_IOCTL_I915_GEM_CONTEXT_CREATE` which is identified by a 32-bit +integer. Such a context should be viewed by user-space as -loosely- +analogous to the idea of a CPU process of an operating system. The i915 +driver guarantees that commands issued to a fixed context are to be +executed so that writes of a previously issued command are seen by +reads of following commands. Actions issued between different contexts +(even if from the same file descriptor) are NOT given that guarantee +and the only way to synchronize across contexts (even from the same +file descriptor) is through the use of fences. At least as far back as +Gen4, also have that a context carries with it a GPU HW context; +the HW context is essentially (most of atleast) the state of a GPU. +In addition to the ordering guarantees, the kernel will restore GPU +state via HW context when commands are issued to a context, this saves +user space the need to restore (most of atleast) the GPU state at the +start of each batchbuffer. The non-deprecated ioctls to submit batchbuffer +work can pass that ID (in the lower bits of drm_i915_gem_execbuffer2::rsvd1) +to identify what context to use with the command. + +The GPU has its own memory management and address space. The kernel +driver maintains the memory translation table for the GPU. For older +GPUs (i.e. those before Gen8), there is a single global such translation +table, a global Graphics Translation Table (GTT). For newer generation +GPUs each context has its own translation table, called Per-Process +Graphics Translation Table (PPGTT). Of important note, is that although +PPGTT is named per-process it is actually per context. When user space +submits a batchbuffer, the kernel walks the list of GEM buffer objects +used by the batchbuffer and guarantees that not only is the memory of +each such GEM buffer object resident but it is also present in the +(PP)GTT. If the GEM buffer object is not yet placed in the (PP)GTT, +then it is given an address. Two consequences of this are: the kernel +needs to edit the batchbuffer submitted to write the correct value of +the GPU address when a GEM BO is assigned a GPU address and the kernel +might evict a different GEM BO from the (PP)GTT to make address room +for another GEM BO. Consequently, the ioctls submitting a batchbuffer +for execution also include a list of all locations within buffers that +refer to GPU-addresses so that the kernel can edit the buffer correctly. +This process is dubbed relocation. + +GEM BO Management Implementation Details +---------------------------------------- + +.. kernel-doc:: drivers/gpu/drm/i915/i915_vma.h + :doc: Virtual Memory Address + +Buffer Object Eviction +---------------------- + +This section documents the interface functions for evicting buffer +objects to make space available in the virtual gpu address spaces. Note +that this is mostly orthogonal to shrinking buffer objects caches, which +has the goal to make main memory (shared with the gpu through the +unified memory architecture) available. + +.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_evict.c + :internal: + +Buffer Object Memory Shrinking +------------------------------ + +This section documents the interface function for shrinking memory usage +of buffer object caches. Shrinking is used to make main memory +available. Note that this is mostly orthogonal to evicting buffer +objects, which has the goal to make space in gpu virtual address spaces. + +.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_shrinker.c + :internal: + Batchbuffer Parsing ------------------- @@ -267,6 +370,12 @@ Batchbuffer Pools .. kernel-doc:: drivers/gpu/drm/i915/i915_gem_batch_pool.c :internal: +User Batchbuffer Execution +-------------------------- + +.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_execbuffer.c + :doc: User command execution + Logical Rings, Logical Ring Contexts and Execlists -------------------------------------------------- @@ -312,28 +421,14 @@ Object Tiling IOCTLs .. kernel-doc:: drivers/gpu/drm/i915/i915_gem_tiling.c :doc: buffer object tiling -Buffer Object Eviction ----------------------- - -This section documents the interface functions for evicting buffer -objects to make space available in the virtual gpu address spaces. Note -that this is mostly orthogonal to shrinking buffer objects caches, which -has the goal to make main memory (shared with the gpu through the -unified memory architecture) available. - -.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_evict.c - :internal: - -Buffer Object Memory Shrinking ------------------------------- +WOPCM +===== -This section documents the interface function for shrinking memory usage -of buffer object caches. Shrinking is used to make main memory -available. Note that this is mostly orthogonal to evicting buffer -objects, which has the goal to make space in gpu virtual address spaces. +WOPCM Layout +------------ -.. kernel-doc:: drivers/gpu/drm/i915/i915_gem_shrinker.c - :internal: +.. kernel-doc:: drivers/gpu/drm/i915/intel_wopcm.c + :doc: WOPCM Layout GuC === @@ -359,6 +454,12 @@ GuC Firmware Layout .. kernel-doc:: drivers/gpu/drm/i915/intel_guc_fwif.h :doc: GuC Firmware Layout +GuC Address Space +----------------- + +.. kernel-doc:: drivers/gpu/drm/i915/intel_guc.c + :doc: GuC Address Space + Tracing ======= diff --git a/Documentation/gpu/kms-properties.csv b/Documentation/gpu/kms-properties.csv index 6b28b014cb7d..07ed22ea3bd6 100644 --- a/Documentation/gpu/kms-properties.csv +++ b/Documentation/gpu/kms-properties.csv @@ -98,5 +98,4 @@ radeon,DVI-I,“coherent”,RANGE,"Min=0, Max=1",Connector,TBD ,,"""underscan vborder""",RANGE,"Min=0, Max=128",Connector,TBD ,Audio,“audio”,ENUM,"{ ""off"", ""on"", ""auto"" }",Connector,TBD ,FMT Dithering,“dither”,ENUM,"{ ""off"", ""on"" }",Connector,TBD -rcar-du,Generic,"""alpha""",RANGE,"Min=0, Max=255",Plane,TBD ,,"""colorkey""",RANGE,"Min=0, Max=0x01ffffff",Plane,TBD diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index f4d0b3476d9c..a7c150d6b63f 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -212,6 +212,24 @@ probably use drm_fb_helper_fbdev_teardown(). Contact: Maintainer of the driver you plan to convert +Clean up mmap forwarding +------------------------ + +A lot of drivers forward gem mmap calls to dma-buf mmap for imported buffers. +And also a lot of them forward dma-buf mmap to the gem mmap implementations. +Would be great to refactor this all into a set of small common helpers. + +Contact: Daniel Vetter + +Put a reservation_object into drm_gem_object +-------------------------------------------- + +This would remove the need for the ->gem_prime_res_obj callback. It would also +allow us to implement generic helpers for waiting for a bo, allowing for quite a +bit of refactoring in the various wait ioctl implementations. + +Contact: Daniel Vetter + idr_init_base() --------------- diff --git a/Documentation/gpu/xen-front.rst b/Documentation/gpu/xen-front.rst new file mode 100644 index 000000000000..d988da7d1983 --- /dev/null +++ b/Documentation/gpu/xen-front.rst @@ -0,0 +1,31 @@ +==================================================== + drm/xen-front Xen para-virtualized frontend driver +==================================================== + +This frontend driver implements Xen para-virtualized display +according to the display protocol described at +include/xen/interface/io/displif.h + +Driver modes of operation in terms of display buffers used +========================================================== + +.. kernel-doc:: drivers/gpu/drm/xen/xen_drm_front.h + :doc: Driver modes of operation in terms of display buffers used + +Buffers allocated by the frontend driver +---------------------------------------- + +.. kernel-doc:: drivers/gpu/drm/xen/xen_drm_front.h + :doc: Buffers allocated by the frontend driver + +Buffers allocated by the backend +-------------------------------- + +.. kernel-doc:: drivers/gpu/drm/xen/xen_drm_front.h + :doc: Buffers allocated by the backend + +Driver limitations +================== + +.. kernel-doc:: drivers/gpu/drm/xen/xen_drm_front.h + :doc: Driver limitations |