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