On Wed, Dec 9, 2020 at 6:24 AM Daniel Vetter daniel@ffwll.ch wrote:

On Wed, Dec 09, 2020 at 02:07:35AM +0530, Sumera Priyadarsini wrote:

...

Update the vkms documentation to contain steps to:

• setup the vkms driver
• run tests using igt

Signed-off-by: Sumera Priyadarsini sylphrenadin@gmail.com ___ Changes in v2:

• Change heading to title case (Daniel)
• Add examples to run tests directly (Daniel)
• Add examples to run subtests (Melissa)

---

Documentation/gpu/vkms.rst | 67 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst index 13bab1d93bb3..d6739fbbe503 100644 --- a/Documentation/gpu/vkms.rst +++ b/Documentation/gpu/vkms.rst @@ -7,6 +7,73 @@ .. kernel-doc:: drivers/gpu/drm/vkms/vkms_drv.c :doc: vkms (Virtual Kernel Modesetting)

+Setup +=====

+The VKMS driver can be setup with the following steps:

+To check if VKMS is loaded, run::

• lsmod | grep vkms

+This should list the VKMS driver. If no output is obtained, then +you need to enable and/or load the VKMS driver. +Ensure that the VKMS driver has been set as a loadable module in your +kernel config file. Do::

• make nconfig
• Go to `Device Drivers> Graphics support`
• Enable `Virtual KMS (EXPERIMENTAL)`

+Compile and build the kernel for the changes to get reflected. +Now, to load the driver, use::

• sudo modprobe vkms

+On running the lsmod command now, the VKMS driver will appear listed. +You can also observe the driver being loaded in the dmesg logs.

+To disable the driver, use ::

• sudo modprobe -r vkms

+Testing With IGT +================

+The IGT GPU Tools is a test suite used specifically for debugging and +development of the DRM drivers. +The IGT Tools can be installed from +`here https://gitlab.freedesktop.org/drm/igt-gpu-tools`_ .

+The tests need to be run without a compositor, so you need to switch to text +only mode. You can do this by::

• sudo systemctl isolate multi-user.target

+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::

• 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>

+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

+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

Does IGT_DEVICE also work with run-tests.sh? Aside from my curious question, patch looks good to me, thanks a lot.

Good catch, it does.

Melissa, IGT_FORCE_DRIVER also works. I think I was used test/kms_flip earlier instead of ./build/test/kms_flip hence the fluke.

Should I add these also to the docs, was wondering if it will get too confusing....

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

...

TODO

-- 2.25.1

-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch