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Diffstat (limited to 'Documentation/gpu/vkms.rst')
| -rw-r--r-- | Documentation/gpu/vkms.rst | 156 |
1 files changed, 115 insertions, 41 deletions
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst index 941f0e7e5eef..1e79e62a6bc4 100644 --- a/Documentation/gpu/vkms.rst +++ b/Documentation/gpu/vkms.rst @@ -51,6 +51,97 @@ To disable the driver, use :: sudo modprobe -r vkms +Configuring With Configfs +========================= + +It is possible to create and configure multiple VKMS instances via configfs. + +Start by mounting configfs and loading VKMS:: + + sudo mount -t configfs none /config + sudo modprobe vkms + +Once VKMS is loaded, ``/config/vkms`` is created automatically. Each directory +under ``/config/vkms`` represents a VKMS instance, create a new one:: + + sudo mkdir /config/vkms/my-vkms + +By default, the instance is disabled:: + + cat /config/vkms/my-vkms/enabled + 0 + +And directories are created for each configurable item of the display pipeline:: + + tree /config/vkms/my-vkms + ├── connectors + ├── crtcs + ├── enabled + ├── encoders + └── planes + +To add items to the display pipeline, create one or more directories under the +available paths. + +Start by creating one or more planes:: + + sudo mkdir /config/vkms/my-vkms/planes/plane0 + +Planes have 1 configurable attribute: + +- type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those + exposed by the "type" property of a plane) + +Continue by creating one or more CRTCs:: + + sudo mkdir /config/vkms/my-vkms/crtcs/crtc0 + +CRTCs have 1 configurable attribute: + +- writeback: Enable or disable writeback connector support by writing 1 or 0 + +Next, create one or more encoders:: + + sudo mkdir /config/vkms/my-vkms/encoders/encoder0 + +Last but not least, create one or more connectors:: + + sudo mkdir /config/vkms/my-vkms/connectors/connector0 + +Connectors have 1 configurable attribute: + +- status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values + as those exposed by the "status" property of a connector) + +To finish the configuration, link the different pipeline items:: + + sudo ln -s /config/vkms/my-vkms/crtcs/crtc0 /config/vkms/my-vkms/planes/plane0/possible_crtcs + sudo ln -s /config/vkms/my-vkms/crtcs/crtc0 /config/vkms/my-vkms/encoders/encoder0/possible_crtcs + sudo ln -s /config/vkms/my-vkms/encoders/encoder0 /config/vkms/my-vkms/connectors/connector0/possible_encoders + +Since at least one primary plane is required, make sure to set the right type:: + + echo "1" | sudo tee /config/vkms/my-vkms/planes/plane0/type + +Once you are done configuring the VKMS instance, enable it:: + + echo "1" | sudo tee /config/vkms/my-vkms/enabled + +Finally, you can remove the VKMS instance disabling it:: + + echo "0" | sudo tee /config/vkms/my-vkms/enabled + +And removing the top level directory and its subdirectories:: + + sudo rm /config/vkms/my-vkms/planes/*/possible_crtcs/* + sudo rm /config/vkms/my-vkms/encoders/*/possible_crtcs/* + sudo rm /config/vkms/my-vkms/connectors/*/possible_encoders/* + sudo rmdir /config/vkms/my-vkms/planes/* + sudo rmdir /config/vkms/my-vkms/crtcs/* + sudo rmdir /config/vkms/my-vkms/encoders/* + sudo rmdir /config/vkms/my-vkms/connectors/* + sudo rmdir /config/vkms/my-vkms + Testing With IGT ================ @@ -68,26 +159,34 @@ To return to graphical mode, do:: sudo systemctl isolate graphical.target -Once you are in text only mode, you can run tests using the --device switch -or IGT_DEVICE variable to specify the device filter for the driver we want -to test. IGT_DEVICE can also be used with the run-test.sh script to run the +Once you are in text only mode, you can run tests using the IGT_FORCE_DRIVER +variable to specify the device filter for the driver we want to test. +IGT_FORCE_DRIVER can also be used with the run-tests.sh script to run the tests for a specific driver:: - sudo ./build/tests/<name of test> --device "sys:/sys/devices/platform/vkms" - sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" ./build/tests/<name of test> - sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" ./scripts/run-tests.sh -t <name of test> + sudo IGT_FORCE_DRIVER="vkms" ./build/tests/<name of test> + sudo IGT_FORCE_DRIVER="vkms" ./scripts/run-tests.sh -t <name of test> For example, to test the functionality of the writeback library, we can run the kms_writeback test:: - sudo ./build/tests/kms_writeback --device "sys:/sys/devices/platform/vkms" - sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" ./build/tests/kms_writeback - sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" ./scripts/run-tests.sh -t kms_writeback + sudo IGT_FORCE_DRIVER="vkms" ./build/tests/kms_writeback + sudo IGT_FORCE_DRIVER="vkms" ./scripts/run-tests.sh -t kms_writeback You can also run subtests if you do not want to run the entire test:: - sudo ./build/tests/kms_flip --run-subtest basic-plain-flip --device "sys:/sys/devices/platform/vkms" - sudo IGT_DEVICE="sys:/sys/devices/platform/vkms" ./build/tests/kms_flip --run-subtest basic-plain-flip + sudo IGT_FORCE_DRIVER="vkms" ./build/tests/kms_flip --run-subtest basic-plain-flip + +Testing With KUnit +================== + +KUnit (Kernel unit testing framework) provides a common framework for unit tests +within the Linux kernel. +More information in ../dev-tools/kunit/index.rst . + +To run the VKMS KUnit tests:: + + tools/testing/kunit/kunit.py run --kunitconfig=drivers/gpu/drm/vkms/tests TODO ==== @@ -102,12 +201,6 @@ Debugging: - kms_plane: some test cases are failing due to timeout on capturing CRC; -- kms_flip: when running test cases in sequence, some successful individual - test cases are failing randomly; when individually, some successful test - cases display in the log the following error:: - - [drm:vkms_prepare_fb [vkms]] ERROR vmap failed: -4 - Virtual hardware (vblank-less) mode: - VKMS already has support for vblanks simulated via hrtimers, which can be @@ -124,24 +217,12 @@ Add Plane Features There's lots of plane features we could add support for: -- Multiple overlay planes. [Good to get started] +- Add background color KMS property[Good to get started]. -- Clearing primary plane: clear primary plane before plane composition (at the - start) for correctness of pixel blend ops. It also guarantees alpha channel - is cleared in the target buffer for stable crc. [Good to get started] +- Scaling. -- ARGB format on primary plane: blend the primary plane into background with - translucent alpha. - -- Support when the primary plane isn't exactly matching the output size: blend - the primary plane into the black background. - -- Full alpha blending on all planes. - -- Rotation, scaling. - -- Additional buffer formats, especially YUV formats for video like NV12. - Low/high bpp RGB formats would also be interesting. +- Additional buffer formats. Low/high bpp RGB formats would be interesting + [Good to get started]. - Async updates (currently only possible on cursor plane using the legacy cursor api). @@ -154,21 +235,14 @@ Runtime Configuration --------------------- We want to be able to reconfigure vkms instance without having to reload the -module. Use/Test-cases: +module through configfs. Use/Test-cases: - Hotplug/hotremove connectors on the fly (to be able to test DP MST handling of compositors). -- Configure planes/crtcs/connectors (we'd need some code to have more than 1 of - them first). - - Change output configuration: Plug/unplug screens, change EDID, allow changing the refresh rate. -The currently proposed solution is to expose vkms configuration through -configfs. All existing module options should be supported through configfs -too. - Writeback support ----------------- |