diff options
Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/drivers.rst | 1 | ||||
| -rw-r--r-- | Documentation/gpu/drm-mm.rst | 20 | ||||
| -rw-r--r-- | Documentation/gpu/drm-uapi.rst | 77 | ||||
| -rw-r--r-- | Documentation/gpu/drm-usage-stats.rst | 1 | ||||
| -rw-r--r-- | Documentation/gpu/panfrost.rst | 40 |
5 files changed, 129 insertions, 10 deletions
diff --git a/Documentation/gpu/drivers.rst b/Documentation/gpu/drivers.rst index 3a52f48215a3..45a12e552091 100644 --- a/Documentation/gpu/drivers.rst +++ b/Documentation/gpu/drivers.rst @@ -18,6 +18,7 @@ GPU Driver Documentation xen-front afbc komeda-kms + panfrost .. only:: subproject and html diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index c19b34b1c0ed..602010cb6894 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -466,40 +466,40 @@ DRM MM Range Allocator Function References .. kernel-doc:: drivers/gpu/drm/drm_mm.c :export: -DRM GPU VA Manager -================== +DRM GPUVM +========= Overview -------- -.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c +.. kernel-doc:: drivers/gpu/drm/drm_gpuvm.c :doc: Overview Split and Merge --------------- -.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c +.. kernel-doc:: drivers/gpu/drm/drm_gpuvm.c :doc: Split and Merge Locking ------- -.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c +.. kernel-doc:: drivers/gpu/drm/drm_gpuvm.c :doc: Locking Examples -------- -.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c +.. kernel-doc:: drivers/gpu/drm/drm_gpuvm.c :doc: Examples -DRM GPU VA Manager Function References --------------------------------------- +DRM GPUVM Function References +----------------------------- -.. kernel-doc:: include/drm/drm_gpuva_mgr.h +.. kernel-doc:: include/drm/drm_gpuvm.h :internal: -.. kernel-doc:: drivers/gpu/drm/drm_gpuva_mgr.c +.. kernel-doc:: drivers/gpu/drm/drm_gpuvm.c :export: DRM Buddy Allocator diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index eef5fd19bc92..632989df3727 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -285,6 +285,83 @@ for GPU1 and GPU2 from different vendors, and a third handler for mmapped regular files. Threads cause additional pain with signal handling as well. +Device reset +============ + +The GPU stack is really complex and is prone to errors, from hardware bugs, +faulty applications and everything in between the many layers. Some errors +require resetting the device in order to make the device usable again. This +section describes the expectations for DRM and usermode drivers when a +device resets and how to propagate the reset status. + +Device resets can not be disabled without tainting the kernel, which can lead to +hanging the entire kernel through shrinkers/mmu_notifiers. Userspace role in +device resets is to propagate the message to the application and apply any +special policy for blocking guilty applications, if any. Corollary is that +debugging a hung GPU context require hardware support to be able to preempt such +a GPU context while it's stopped. + +Kernel Mode Driver +------------------ + +The KMD is responsible for checking if the device needs a reset, and to perform +it as needed. Usually a hang is detected when a job gets stuck executing. KMD +should keep track of resets, because userspace can query any time about the +reset status for a specific context. This is needed to propagate to the rest of +the stack that a reset has happened. Currently, this is implemented by each +driver separately, with no common DRM interface. Ideally this should be properly +integrated at DRM scheduler to provide a common ground for all drivers. After a +reset, KMD should reject new command submissions for affected contexts. + +User Mode Driver +---------------- + +After command submission, UMD should check if the submission was accepted or +rejected. After a reset, KMD should reject submissions, and UMD can issue an +ioctl to the KMD to check the reset status, and this can be checked more often +if the UMD requires it. After detecting a reset, UMD will then proceed to report +it to the application using the appropriate API error code, as explained in the +section below about robustness. + +Robustness +---------- + +The only way to try to keep a graphical API context working after a reset is if +it complies with the robustness aspects of the graphical API that it is using. + +Graphical APIs provide ways to applications to deal with device resets. However, +there is no guarantee that the app will use such features correctly, and a +userspace that doesn't support robust interfaces (like a non-robust +OpenGL context or API without any robustness support like libva) leave the +robustness handling entirely to the userspace driver. There is no strong +community consensus on what the userspace driver should do in that case, +since all reasonable approaches have some clear downsides. + +OpenGL +~~~~~~ + +Apps using OpenGL should use the available robust interfaces, like the +extension ``GL_ARB_robustness`` (or ``GL_EXT_robustness`` for OpenGL ES). This +interface tells if a reset has happened, and if so, all the context state is +considered lost and the app proceeds by creating new ones. There's no consensus +on what to do to if robustness is not in use. + +Vulkan +~~~~~~ + +Apps using Vulkan should check for ``VK_ERROR_DEVICE_LOST`` for submissions. +This error code means, among other things, that a device reset has happened and +it needs to recreate the contexts to keep going. + +Reporting causes of resets +-------------------------- + +Apart from propagating the reset through the stack so apps can recover, it's +really useful for driver developers to learn more about what caused the reset in +the first place. DRM devices should make use of devcoredump to store relevant +information about the reset, so this information can be added to user bug +reports. + .. _drm_driver_ioctl: IOCTL Support on Device Nodes diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst index 044e6b2ed1be..7aca5c7a7b1d 100644 --- a/Documentation/gpu/drm-usage-stats.rst +++ b/Documentation/gpu/drm-usage-stats.rst @@ -169,3 +169,4 @@ Driver specific implementations ------------------------------- :ref:`i915-usage-stats` +:ref:`panfrost-usage-stats` diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst new file mode 100644 index 000000000000..b80e41f4b2c5 --- /dev/null +++ b/Documentation/gpu/panfrost.rst @@ -0,0 +1,40 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +========================= + drm/Panfrost Mali Driver +========================= + +.. _panfrost-usage-stats: + +Panfrost DRM client usage stats implementation +============================================== + +The drm/Panfrost driver implements the DRM client usage stats specification as +documented in :ref:`drm-client-usage-stats`. + +Example of the output showing the implemented key value pairs and entirety of +the currently possible format options: + +:: + pos: 0 + flags: 02400002 + mnt_id: 27 + ino: 531 + drm-driver: panfrost + drm-client-id: 14 + drm-engine-fragment: 1846584880 ns + drm-cycles-fragment: 1424359409 + drm-maxfreq-fragment: 799999987 Hz + drm-curfreq-fragment: 799999987 Hz + drm-engine-vertex-tiler: 71932239 ns + drm-cycles-vertex-tiler: 52617357 + drm-maxfreq-vertex-tiler: 799999987 Hz + drm-curfreq-vertex-tiler: 799999987 Hz + drm-total-memory: 290 MiB + drm-shared-memory: 0 MiB + drm-active-memory: 226 MiB + drm-resident-memory: 36496 KiB + drm-purgeable-memory: 128 KiB + +Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`. +`drm-curfreq-` values convey the current operating frequency for that engine. |