[PATCH V2] drm/vkms: Add setup and testing information

[Daniel Vetter]

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 at 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.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> +
>  TODO
>  ====
>  
> -- 
> 2.25.1
> 

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