[igt-dev] [PATCH v3] tests/kms_plane: Handle hw without legacy gamma support

[Rob Clark]

On Mon, Aug 7, 2023 at 11:29 AM Juha-Pekka Heikkila
<juhapekka.heikkila at gmail.com> wrote:
>
> Hi Rob,
>
> On 7.8.2023 19.54, Rob Clark wrote:
> > From: Rob Clark <robdclark at chromium.org>
> >
> > Skip the tests which require legacy gamma, instead of failing, if the hw
> > does not support legacy gamma.
> >
> > v2: igt_require(lut_size > 0) instead
> > v3: simplify patch
> >
> > Signed-off-by: Rob Clark <robdclark at chromium.org>
> > ---
> >   tests/kms_plane.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/tests/kms_plane.c b/tests/kms_plane.c
> > index 67cff61d6cd1..44cad2bf2491 100644
> > --- a/tests/kms_plane.c
> > +++ b/tests/kms_plane.c
> > @@ -469,6 +469,8 @@ static void set_legacy_lut(data_t *data, enum pipe pipe,
> >       lut_size = crtc->gamma_size;
> >       drmModeFreeCrtc(crtc);
> >
> > +     igt_require(lut_size > 0);
> > +
>
> Is this something you really want on your hw? This lut stuff is
> originally coming from this patch
>
> https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/commit/093fa482371795c3aa246509994eb21907f501b9
>
> where it is mentioned:
>
> ---
> We also abuse the legacy LUT to drop the precision down to 6 bits
> so that still errors causes by the RGB<->YCbCr conversion end up
> being ignored.
> ---
>
> With your change you'd skip testing of all available pixel
> formats/modifiers combos on your driver while originally this feature is
> mostly intended just to avoid hitting Intel hw related anomalies. Do
> those tests work for you if you just not set that lut?

Hmm, I get failures, but at least part of that seems to be igt being
unaware of qcom/msm modifiers..  I'll need to investigate further

BR,
-R

> /Juha-Pekka
>
> >       lut = malloc(sizeof(uint16_t) * lut_size);
> >
> >       for (i = 0; i < lut_size; i++)
>