[PATCH] drm/amd/display: Verify Gamma & Degamma LUT sizes in amdgpu_dm_atomic_check

Mark Yacoub markyacoub at chromium.org
Mon Jun 14 14:48:57 UTC 2021


hmm I see, thanks for the heads up, I'll double check why it uses
google email for sending.
wrt the assignment in the if clauses, are those typically frowned upon?
Thanks!

On Fri, Jun 11, 2021 at 4:17 PM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> Just a heads up, your sender email and your signed-off-by don't match
> and you had some assignments in if clauses.  I've fixed those up.
>
> Alex
>
>
> On Fri, Jun 11, 2021 at 1:35 PM Alex Deucher <alexdeucher at gmail.com> wrote:
> >
> > Applied.  Thanks!
> >
> > On Thu, Jun 10, 2021 at 5:14 PM Harry Wentland <harry.wentland at amd.com> wrote:
> > >
> > >
> > >
> > > On 2021-06-07 10:53 a.m., Mark Yacoub wrote:
> > > > On Fri, Jun 4, 2021 at 4:17 PM Harry Wentland <harry.wentland at amd.com> wrote:
> > > >>
> > > >>
> > > >>
> > > >> On 2021-06-04 1:01 p.m., Mark Yacoub wrote:
> > > >>> From: Mark Yacoub <markyacoub at google.com>
> > > >>>
> > > >>> For each CRTC state, check the size of Gamma and Degamma LUTs  so
> > > >>> unexpected and larger sizes wouldn't slip through.
> > > >>>
> > > >>> TEST: IGT:kms_color::pipe-invalid-gamma-lut-sizes
> > > >>>
> > > >>> Signed-off-by: Mark Yacoub <markyacoub at chromium.org>
> > > >>> Change-Id: I9d513a38e8ac2af1b4bf802e1feb1a4d726fba4c
> > > >>> ---
> > > >>>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 ++
> > > >>>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  1 +
> > > >>>  .../amd/display/amdgpu_dm/amdgpu_dm_color.c   | 40 ++++++++++++++++---
> > > >>>  3 files changed, 38 insertions(+), 6 deletions(-)
> > > >>>
> > > >>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > >>> index 38d497d30dba8..f6cd522b42a80 100644
> > > >>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > >>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > > >>> @@ -9402,6 +9402,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
> > > >>>                       dm_old_crtc_state->dsc_force_changed == false)
> > > >>>                       continue;
> > > >>>
> > > >>> +             if ((ret = amdgpu_dm_verify_lut_sizes(new_crtc_state)))
> > > >>> +                     goto fail;
> > > >>> +
> > > >>>               if (!new_crtc_state->enable)
> > > >>>                       continue;
> > > >>>
> > > >>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > > >>> index 8bfe901cf2374..1b77cd2612691 100644
> > > >>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > > >>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> > > >>> @@ -541,6 +541,7 @@ void amdgpu_dm_trigger_timing_sync(struct drm_device *dev);
> > > >>>  #define MAX_COLOR_LEGACY_LUT_ENTRIES 256
> > > >>>
> > > >>>  void amdgpu_dm_init_color_mod(void);
> > > >>> +int amdgpu_dm_verify_lut_sizes(const struct drm_crtc_state *crtc_state);
> > > >>>  int amdgpu_dm_update_crtc_color_mgmt(struct dm_crtc_state *crtc);
> > > >>>  int amdgpu_dm_update_plane_color_mgmt(struct dm_crtc_state *crtc,
> > > >>>                                     struct dc_plane_state *dc_plane_state);
> > > >>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> > > >>> index 157fe4efbb599..da6f9fcc0b415 100644
> > > >>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> > > >>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> > > >>> @@ -284,6 +284,37 @@ static int __set_input_tf(struct dc_transfer_func *func,
> > > >>>       return res ? 0 : -ENOMEM;
> > > >>>  }
> > > >>>
> > > >>> +/**
> > > >>> + * Verifies that the Degamma and Gamma LUTs attached to the |crtc_state| are of
> > > >>> + * the expected size.
> > > >>> + * Returns 0 on success.
> > > >>> + */
> > > >>> +int amdgpu_dm_verify_lut_sizes(const struct drm_crtc_state *crtc_state)
> > > >>> +{
> > > >>> +     const struct drm_color_lut *lut = NULL;
> > > >>> +     uint32_t size = 0;
> > > >>> +
> > > >>> +     lut = __extract_blob_lut(crtc_state->degamma_lut, &size);
> > > >>> +     if (lut && size != MAX_COLOR_LUT_ENTRIES) {
> > > >>
> > > >> Isn't the point of the LUT size that it can be variable? Did you observe any
> > > >> problems with LUTs that are not of size 4096?
> > > > Is it supposed to be variable?
> > > > I'm basing my knowledge of LUTs on this IGT Test:
> > > > https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/kms_color_helper.c#L281>> It does check for invalid sizes and for the exact size, giving me the
> > > > impression that it's not too flexible.
> > > > Is variability of size an AMD specific behavior or should it be a DRM behavior?
> > > >>
> > > >> Legacy X-based userspace will give us 256 size LUTs. We can't break support for
> > > >> that. See MAX_COLOR_LEGACY_LUT_ENTRIES.
> > > > In the new function `amdgpu_dm_verify_lut_sizes`, I maintained parity
> > > > with the old behavior. In `amdgpu_dm_update_crtc_color_mgmt`, the
> > > > degamma size is only checked against `MAX_COLOR_LUT_ENTRIES` while
> > > > regamma_size size is checked against both MAX_COLOR_LUT_ENTRIES and
> > > > MAX_COLOR_LEGACY_LUT_ENTRIES:
> > > > https://gitlab.freedesktop.org/agd5f/linux/-/blob/amd-staging-drm-next/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c#L321>> Also, in the definition of MAX_COLOR_LEGACY_LUT_ENTRIES, it mentions
> > > > "Legacy gamm[sic] LUT" not degamma:
> > > > https://gitlab.freedesktop.org/agd5f/linux/-/blame/amd-staging-drm-next/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h#L616>> As well as the commit when it was introduced, it seems to be handling
> > > > gammas rather than degamma LUTs:
> > > > https://gitlab.freedesktop.org/agd5f/linux/-/commit/086247a4b2fba49800b27807f22bb894cd8363fb>> Let me know if this would be a bug in the old behavior and I can fix
> > > > it, or if i'm missing something.
> > >
> > > Ah, yes, you're right, of course. Thanks for walking me through it. :)
> > >
> > > Reviewed-by: Harry Wentland <harry.wentland at amd.com>
> > >
> > > Harry
> > >
> > > >>
> > > >> Harry
> > > >>
> > > >>> +             DRM_DEBUG_DRIVER(
> > > >>> +                     "Invalid Degamma LUT size. Should be %u but got %u.\n",
> > > >>> +                     MAX_COLOR_LUT_ENTRIES, size);
> > > >>> +             return -EINVAL;
> > > >>> +     }
> > > >>> +
> > > >>> +     lut = __extract_blob_lut(crtc_state->gamma_lut, &size);
> > > >>> +     if (lut && size != MAX_COLOR_LUT_ENTRIES &&
> > > >>> +         size != MAX_COLOR_LEGACY_LUT_ENTRIES) {
> > > >>> +             DRM_DEBUG_DRIVER(
> > > >>> +                     "Invalid Gamma LUT size. Should be %u (or %u for legacy) but got %u.\n",
> > > >>> +                     MAX_COLOR_LUT_ENTRIES, MAX_COLOR_LEGACY_LUT_ENTRIES,
> > > >>> +                     size);
> > > >>> +             return -EINVAL;
> > > >>> +     }
> > > >>> +
> > > >>> +     return 0;
> > > >>> +}
> > > >>> +
> > > >>>  /**
> > > >>>   * amdgpu_dm_update_crtc_color_mgmt: Maps DRM color management to DC stream.
> > > >>>   * @crtc: amdgpu_dm crtc state
> > > >>> @@ -317,14 +348,11 @@ int amdgpu_dm_update_crtc_color_mgmt(struct dm_crtc_state *crtc)
> > > >>>       bool is_legacy;
> > > >>>       int r;
> > > >>>
> > > >>> -     degamma_lut = __extract_blob_lut(crtc->base.degamma_lut, &degamma_size);
> > > >>> -     if (degamma_lut && degamma_size != MAX_COLOR_LUT_ENTRIES)
> > > >>> -             return -EINVAL;
> > > >>> +     if ((r = amdgpu_dm_verify_lut_sizes(&crtc->base)))
> > > >>> +             return r;
> > > >>>
> > > >>> +     degamma_lut = __extract_blob_lut(crtc->base.degamma_lut, &degamma_size);
> > > >>>       regamma_lut = __extract_blob_lut(crtc->base.gamma_lut, &regamma_size);
> > > >>> -     if (regamma_lut && regamma_size != MAX_COLOR_LUT_ENTRIES &&
> > > >>> -         regamma_size != MAX_COLOR_LEGACY_LUT_ENTRIES)
> > > >>> -             return -EINVAL;
> > > >>>
> > > >>>       has_degamma =
> > > >>>               degamma_lut && !__is_lut_linear(degamma_lut, degamma_size);
> > > >>>
> > > >>
> > > > -Mark
> > > >
> > >


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