Re: [Intel-gfx] [PATCH v5 2/3] drm: Add Gamma and Degamma LUT sizes props to drm_crtc to validate.

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Nov 04, 2021 at 05:15:43PM -0400, Ilia Mirkin wrote:
> On Thu, Nov 4, 2021 at 4:03 PM Mark Yacoub <markyacoub@chromium.org> wrote:
> >
> > From: Mark Yacoub <markyacoub@google.com>
> >
> > [Why]
> > 1. drm_atomic_helper_check doesn't check for the LUT sizes of either Gamma
> > or Degamma props in the new CRTC state, allowing any invalid size to
> > be passed on.
> > 2. Each driver has its own LUT size, which could also be different for
> > legacy users.
> >
> > [How]
> > 1. Create |degamma_lut_size| and |gamma_lut_size| to save the LUT sizes
> > assigned by the driver when it's initializing its color and CTM
> > management.
> > 2. Create drm_atomic_helper_check_crtc which is called by
> > drm_atomic_helper_check to check the LUT sizes saved in drm_crtc that
> > they match the sizes in the new CRTC state.
> > 3. As the LUT size check now happens in drm_atomic_helper_check, remove
> > the lut check in intel_color.c
> >
> > Resolves: igt@kms_color@pipe-A-invalid-gamma-lut-sizes on MTK
> > Tested on Zork (amdgpu) and Jacuzzi (mediatek), volteer (TGL)
> >
> > v3:
> > 1. Check for lut pointer inside drm_check_lut_size.
> >
> > v2:
> > 1. Remove the rename to a parent commit.
> > 2. Create a drm drm_check_lut_size instead of intel only function.
> >
> > v1:
> > 1. Fix typos
> > 2. Remove the LUT size check from intel driver
> > 3. Rename old LUT check to indicate it's a channel change
> >
> > Signed-off-by: Mark Yacoub <markyacoub@chromium.org>
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c        | 52 ++++++++++++++++++++++
> >  drivers/gpu/drm/drm_color_mgmt.c           | 19 ++++++++
> >  drivers/gpu/drm/i915/display/intel_color.c | 32 ++++++-------
> >  include/drm/drm_atomic_helper.h            |  1 +
> >  include/drm/drm_color_mgmt.h               |  3 ++
> >  include/drm/drm_crtc.h                     | 11 +++++
> >  6 files changed, 99 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index bc3487964fb5e..548e5d8221fb4 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -929,6 +929,54 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
> >  }
> >  EXPORT_SYMBOL(drm_atomic_helper_check_planes);
> >
> > +/**
> > + * drm_atomic_helper_check_crtcs - validate state object for CRTC changes
> > + * @state: the driver state object
> > + *
> > + * Check the CRTC state object such as the Gamma/Degamma LUT sizes if the new
> > + * state holds them.
> > + *
> > + * RETURNS:
> > + * Zero for success or -errno
> > + */
> > +int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state)
> > +{
> > +       struct drm_crtc *crtc;
> > +       struct drm_crtc_state *new_crtc_state;
> > +       int i;
> > +
> > +       for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> > +               if (!new_crtc_state->color_mgmt_changed)
> > +                       continue;
> > +
> > +               if (drm_check_lut_size(new_crtc_state->gamma_lut,
> > +                                      crtc->gamma_lut_size) ||
> > +                   drm_check_lut_size(new_crtc_state->gamma_lut,
> > +                                      crtc->gamma_size)) {
> > +                       drm_dbg_state(
> > +                               state->dev,
> > +                               "Invalid Gamma LUT size. Expected %u/%u, got %u.\n",
> > +                               crtc->gamma_lut_size, crtc->gamma_size,
> > +                               drm_color_lut_size(new_crtc_state->gamma_lut));
> > +                       return -EINVAL;
> > +               }
> > +
> > +               if (drm_check_lut_size(new_crtc_state->degamma_lut,
> > +                                      crtc->degamma_lut_size)) {
> > +                       drm_dbg_state(
> > +                               state->dev,
> > +                               "Invalid Degamma LUT size. Expected %u, got %u.\n",
> > +                               crtc->degamma_lut_size,
> > +                               drm_color_lut_size(
> > +                                       new_crtc_state->degamma_lut));
> > +                       return -EINVAL;
> > +               }
> > +       }
> > +
> > +       return 0;
> > +}
> > +EXPORT_SYMBOL(drm_atomic_helper_check_crtcs);
> > +
> >  /**
> >   * drm_atomic_helper_check - validate state object
> >   * @dev: DRM device
> > @@ -974,6 +1022,10 @@ int drm_atomic_helper_check(struct drm_device *dev,
> >         if (ret)
> >                 return ret;
> >
> > +       ret = drm_atomic_helper_check_crtcs(state);
> > +       if (ret)
> > +               return ret;
> > +
> >         if (state->legacy_cursor_update)
> >                 state->async_update = !drm_atomic_helper_async_check(dev, state);
> >
> > diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
> > index 16a07f84948f3..c85094223b535 100644
> > --- a/drivers/gpu/drm/drm_color_mgmt.c
> > +++ b/drivers/gpu/drm/drm_color_mgmt.c
> > @@ -166,6 +166,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
> >         struct drm_mode_config *config = &dev->mode_config;
> >
> >         if (degamma_lut_size) {
> > +               crtc->degamma_lut_size = degamma_lut_size;
> >                 drm_object_attach_property(&crtc->base,
> >                                            config->degamma_lut_property, 0);
> >                 drm_object_attach_property(&crtc->base,
> > @@ -178,6 +179,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
> >                                            config->ctm_property, 0);
> >
> >         if (gamma_lut_size) {
> > +               crtc->gamma_lut_size = gamma_lut_size;
> >                 drm_object_attach_property(&crtc->base,
> >                                            config->gamma_lut_property, 0);
> >                 drm_object_attach_property(&crtc->base,
> > @@ -506,6 +508,23 @@ const char *drm_get_color_range_name(enum drm_color_range range)
> >         return color_range_name[range];
> >  }
> >
> > +/**
> > + * drm_check_lut_size - Checks if LUT size matches the driver expected size.
> > + * @lut: blob containing the LUT
> > + * @expected_size: driver expected LUT size
> > + *
> > + * Returns -EINVAL on mismatch, 0 on match.
> > + */
> > +int drm_check_lut_size(const struct drm_property_blob *lut,
> > +                      uint32_t expected_size)
> > +{
> > +       if (!lut)
> > +               return 0;
> > +
> > +       return drm_color_lut_size(lut) != expected_size ? -EINVAL : 0;
> > +}
> > +EXPORT_SYMBOL(drm_check_lut_size);
> > +
> >  /**
> >   * drm_plane_create_color_properties - color encoding related plane properties
> >   * @plane: plane object
> > diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
> > index 1469871d21ff9..0fe4b2359812a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_color.c
> > +++ b/drivers/gpu/drm/i915/display/intel_color.c
> > @@ -1262,23 +1262,6 @@ intel_color_add_affected_planes(struct intel_crtc_state *new_crtc_state)
> >         return 0;
> >  }
> >
> > -static int check_lut_size(const struct drm_property_blob *lut, int expected)
> > -{
> > -       int len;
> > -
> > -       if (!lut)
> > -               return 0;
> > -
> > -       len = drm_color_lut_size(lut);
> > -       if (len != expected) {
> > -               DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n",
> > -                             len, expected);
> > -               return -EINVAL;
> > -       }
> > -
> > -       return 0;
> > -}
> > -
> >  static int test_luts(const struct drm_property_blob *lut, u32 tests)
> >  {
> >         const struct drm_color_lut *entry;
> > @@ -1336,9 +1319,20 @@ static int check_luts(const struct intel_crtc_state *crtc_state)
> >         degamma_channels_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
> >         gamma_channels_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
> >
> > -       if (check_lut_size(degamma_lut, degamma_length) ||
> > -           check_lut_size(gamma_lut, gamma_length))
> > +       if (drm_check_lut_size(degamma_lut, degamma_length)) {
> > +               drm_dbg_state(
> > +                       &dev_priv->drm,
> > +                       "Invalid Degamma LUT size. Expected %u, got %u.\n",
> > +                       degamma_length, drm_color_lut_size(degamma_lut));
> >                 return -EINVAL;
> > +       }
> > +
> > +       if (drm_check_lut_size(gamma_lut, gamma_length)) {
> > +               drm_dbg_state(&dev_priv->drm,
> > +                             "Invalid Gamma LUT size. Expected %u, got %u.\n",
> > +                             degamma_length, drm_color_lut_size(gamma_lut));
> > +               return -EINVAL;
> > +       }
> >
> >         if (test_luts(degamma_lut, degamma_channels_tests) ||
> >             test_luts(gamma_lut, gamma_channels_tests))
> > diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> > index 4045e2507e11c..a22d32a7a8719 100644
> > --- a/include/drm/drm_atomic_helper.h
> > +++ b/include/drm/drm_atomic_helper.h
> > @@ -38,6 +38,7 @@ struct drm_atomic_state;
> >  struct drm_private_obj;
> >  struct drm_private_state;
> >
> > +int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state);
> >  int drm_atomic_helper_check_modeset(struct drm_device *dev,
> >                                 struct drm_atomic_state *state);
> >  int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
> > diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
> > index 3537f3eeb3872..cb2d74719f2d5 100644
> > --- a/include/drm/drm_color_mgmt.h
> > +++ b/include/drm/drm_color_mgmt.h
> > @@ -74,6 +74,9 @@ static inline int drm_color_lut_size(const struct drm_property_blob *blob)
> >         return blob->length / sizeof(struct drm_color_lut);
> >  }
> >
> > +int drm_check_lut_size(const struct drm_property_blob *lut,
> > +                      uint32_t expected_size);
> > +
> >  enum drm_color_encoding {
> >         DRM_COLOR_YCBCR_BT601,
> >         DRM_COLOR_YCBCR_BT709,
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 2deb15d7e1610..4fd1c9a4bbba8 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -1072,6 +1072,17 @@ struct drm_crtc {
> >         /** @funcs: CRTC control functions */
> >         const struct drm_crtc_funcs *funcs;
> >
> > +       /**
> > +        * @degamma_lut_size: Size of degamma LUT.
> > +        */
> > +       size_t degamma_lut_size;
> > +
> > +       /**
> > +        * @gamma_lut_size: Size of Gamma LUT. Not used by legacy userspace such as
> > +        * X, which doesn't support large lut sizes.
> > +        */
> > +       size_t gamma_lut_size;
> > +
> 
> On NVIDIA hardware, multiple LUT sizes are supported. We do this check in e.g.
> 
> drivers/gpu/drm/nouveau/dispnv50/base907c.c:base907c_ilut
> 
> So I don't think a single sizes at the CRTC level makes sense.

Same on i915. While atm we do restrict things to just two LUT sizes per
crtc (for legacy vs. GAMMA_LUT) there are plans to potentially expose
an arbitrary number of LUT modes.

-- 
Ville Syrjälä
Intel