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From:   Daniel Latypov <dlatypov@google.com>
Date:   Tue, 31 May 2022 13:42:36 -0700
Message-ID: <CAGS_qxoWTo+TqAMOaoD=XEQhFp0K0QN4LS4XRQxFR9aTv=XmfA@mail.gmail.com>
Subject: Re: [RFC PATCH 1/1] drm/format-helper: Add KUnit tests for drm_fb_xrgb8888_to_rgb332()
To:     =?UTF-8?B?Sm9zw6kgRXhww7NzaXRv?= <jose.exposito89@gmail.com>
Cc:     Maxime Ripard <maxime@cerno.tech>, kunit-dev@googlegroups.com,
        javierm@redhat.com, tzimmermann@suse.de,
        maarten.lankhorst@linux.intel.com, airlied@linux.ie,
        daniel@ffwll.ch, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
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On Tue, May 31, 2022 at 11:45 AM Jos=C3=A9 Exp=C3=B3sito
<jose.exposito89@gmail.com> wrote:
> >
> > From above, a)
> > Specifically here, it'd be encouraged to instead do
> >   depends on DRM && KUNIT=3Dy && DRM_KMS_HELPER
>
> My first attempt was to go with:
>
>         depends on KUNIT=3Dy && DRM && DRM_KMS_HELPER
>
> However, when I try to run the tests I get this error:
>
>         $ ./tools/testing/kunit/kunit.py run --kunitconfig=3Ddrivers/gpu/=
drm --arch=3Dx86_64
>         Regenerating .config ...
>         Populating config with:
>         $ make ARCH=3Dx86_64 olddefconfig O=3D.kunit
>         ERROR:root:Not all Kconfig options selected in kunitconfig were i=
n the generated .config.
>         This is probably due to unsatisfied dependencies.
>         Missing: CONFIG_DRM_KMS_HELPER=3Dy, CONFIG_DRM_FORMAR_HELPER_TEST=
=3Dy
>
> I wasn't able to figure out why that was happening, so I decided to use
> "select", which seems to solve the problem.
>
> Do you know why this could be happening?

Ah, you should probably ignore my suggestion then.

Looking at the Kconfig file, it's defined as
  config DRM_KMS_HELPER
  tristate
  depends on DRM
  help
    CRTC helpers for KMS drivers.

Notably, the config lacks a description string.
IIUC, this makes it a "hidden" kconfig option, i.e. you can't directly
select it yourself in a .config, it must be selected by another
kconfig option.

E.g. you can try selecting it manually and see it fail via:
$ ./tools/testing/kunit/kunit.py config --arch=3Dx86_64
--kconfig_add=3DCONFIG_DRM=3Dy --kconfig_add=3DCONFIG_DRM_KMS_HELPER=3Dy
...
Missing: CONFIG_DRM_KMS_HELPER=3Dy

So having the test select it makes the most sense, unless there's a
better kconfig option to automatically select it (I have no idea,
someone with knowledge of the DRM code might though).

Daniel