[PATCH 3/4] drm: Extend color correction to support 3D-CLU

Laurent Pinchart laurent.pinchart at ideasonboard.com
Mon Dec 21 18:38:44 UTC 2020


Hi Daniel,

On Mon, Dec 21, 2020 at 07:36:22PM +0100, Daniel Vetter wrote:
> On Mon, Dec 21, 2020 at 2:57 AM Laurent Pinchart wrote:
> >
> > From: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
> >
> > Extend the existing color management properties to support provision
> > of a 3D cubic look up table, allowing for color specific adjustments.
> >
> > Signed-off-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
> > Co-developed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> 
> Assuming this is meant for merging to upstream: Needs igt + open
> userspace in a compositor that cares enough.

Please see the cover letter :-) Feedback on what an appropriate
userspace would be would be appreciated.

> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c       |  1 +
> >  drivers/gpu/drm/drm_atomic_state_helper.c |  3 ++
> >  drivers/gpu/drm/drm_atomic_uapi.c         | 10 ++++++
> >  drivers/gpu/drm/drm_color_mgmt.c          | 41 +++++++++++++++++++----
> >  drivers/gpu/drm/drm_mode_config.c         | 14 ++++++++
> >  include/drm/drm_crtc.h                    |  9 +++++
> >  include/drm/drm_mode_config.h             | 11 ++++++
> >  7 files changed, 82 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index ba1507036f26..0f54897d3c8d 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -3558,6 +3558,7 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> >         replaced  = drm_property_replace_blob(&crtc_state->degamma_lut, NULL);
> >         replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
> >         replaced |= drm_property_replace_blob(&crtc_state->gamma_lut, blob);
> > +       replaced |= drm_property_replace_blob(&crtc_state->cubic_lut, NULL);
> >         crtc_state->color_mgmt_changed |= replaced;
> >
> >         ret = drm_atomic_commit(state);
> > diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> > index ddcf5c2c8e6a..61c685b50677 100644
> > --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> > @@ -141,6 +141,8 @@ void __drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc,
> >                 drm_property_blob_get(state->ctm);
> >         if (state->gamma_lut)
> >                 drm_property_blob_get(state->gamma_lut);
> > +       if (state->cubic_lut)
> > +               drm_property_blob_get(state->cubic_lut);
> >         state->mode_changed = false;
> >         state->active_changed = false;
> >         state->planes_changed = false;
> > @@ -213,6 +215,7 @@ void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc_state *state)
> >         drm_property_blob_put(state->degamma_lut);
> >         drm_property_blob_put(state->ctm);
> >         drm_property_blob_put(state->gamma_lut);
> > +       drm_property_blob_put(state->cubic_lut);
> >  }
> >  EXPORT_SYMBOL(__drm_atomic_helper_crtc_destroy_state);
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> > index 268bb69c2e2f..07229acab71c 100644
> > --- a/drivers/gpu/drm/drm_atomic_uapi.c
> > +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> > @@ -471,6 +471,14 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> >                                         &replaced);
> >                 state->color_mgmt_changed |= replaced;
> >                 return ret;
> > +       } else if (property == config->cubic_lut_property) {
> > +               ret = drm_atomic_replace_property_blob_from_id(dev,
> > +                                       &state->cubic_lut,
> > +                                       val,
> > +                                       -1, sizeof(struct drm_color_lut),
> > +                                       &replaced);
> > +               state->color_mgmt_changed |= replaced;
> > +               return ret;
> >         } else if (property == config->prop_out_fence_ptr) {
> >                 s32 __user *fence_ptr = u64_to_user_ptr(val);
> >
> > @@ -516,6 +524,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
> >                 *val = (state->ctm) ? state->ctm->base.id : 0;
> >         else if (property == config->gamma_lut_property)
> >                 *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
> > +       else if (property == config->cubic_lut_property)
> > +               *val = (state->cubic_lut) ? state->cubic_lut->base.id : 0;
> >         else if (property == config->prop_out_fence_ptr)
> >                 *val = 0;
> >         else if (property == crtc->scaling_filter_property)
> > diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
> > index 3bcabc2f6e0e..85bbbc8ce8e5 100644
> > --- a/drivers/gpu/drm/drm_color_mgmt.c
> > +++ b/drivers/gpu/drm/drm_color_mgmt.c
> > @@ -33,7 +33,7 @@
> >  /**
> >   * DOC: overview
> >   *
> > - * Color management or color space adjustments is supported through a set of 5
> > + * Color management or color space adjustments is supported through a set of 7
> >   * properties on the &drm_crtc object. They are set up by calling
> >   * drm_crtc_enable_color_mgmt().
> >   *
> > @@ -60,7 +60,7 @@
> >   * “CTM”:
> >   *     Blob property to set the current transformation matrix (CTM) apply to
> >   *     pixel data after the lookup through the degamma LUT and before the
> > - *     lookup through the gamma LUT. The data is interpreted as a struct
> > + *     lookup through the cubic LUT. The data is interpreted as a struct
> >   *     &drm_color_ctm.
> >   *
> >   *     Setting this to NULL (blob property value set to 0) means a
> > @@ -68,13 +68,40 @@
> >   *     boot-up state too. Drivers can access the blob for the color conversion
> >   *     matrix through &drm_crtc_state.ctm.
> >   *
> > + * ”CUBIC_LUT”:
> > + *     Blob property to set the cubic (3D) lookup table performing color
> > + *     mapping after the transformation matrix and before the lookup through
> > + *     the gamma LUT. Unlike the degamma and gamma LUTs that map color
> > + *     components independently, the 3D LUT converts an input color to an
> > + *     output color by indexing into the 3D table using the color components
> > + *     as a 3D coordinate. The LUT is subsampled as 8-bit (or more) precision
> > + *     would require too much storage space in the hardware, so the precision
> > + *     of the color components is reduced before the look up, and the low
> > + *     order bits may be used to interpolate between the nearest points in 3D
> > + *     space.
> > + *
> > + *     The data is interpreted as an array of &struct drm_color_lut elements.
> > + *     Hardware might choose not to use the full precision of the LUT
> > + *     elements.
> > + *
> > + *     Setting this to NULL (blob property value set to 0) means the output
> > + *     color is identical to the input color. This is generally the driver
> > + *     boot-up state too. Drivers can access this blob through
> > + *     &drm_crtc_state.cubic_lut.
> > + *
> > + * ”CUBIC_LUT_SIZE”:
> > + *     Unsigned range property to give the size of the lookup table to be set
> > + *     on the CUBIC_LUT property (the size depends on the underlying hardware).
> > + *     If drivers support multiple LUT sizes then they should publish the
> > + *     largest size, and sub-sample smaller sized LUTs appropriately.
> > + *
> >   * “GAMMA_LUT”:
> >   *     Blob property to set the gamma lookup table (LUT) mapping pixel data
> > - *     after the transformation matrix to data sent to the connector. The
> > - *     data is interpreted as an array of &struct drm_color_lut elements.
> > - *     Hardware might choose not to use the full precision of the LUT elements
> > - *     nor use all the elements of the LUT (for example the hardware might
> > - *     choose to interpolate between LUT[0] and LUT[4]).
> > + *     after the cubic LUT to data sent to the connector. The data is
> > + *     interpreted as an array of &struct drm_color_lut elements. Hardware
> > + *     might choose not to use the full precision of the LUT elements nor use
> > + *     all the elements of the LUT (for example the hardware might choose to
> > + *     interpolate between LUT[0] and LUT[4]).
> >   *
> >   *     Setting this to NULL (blob property value set to 0) means a
> >   *     linear/pass-thru gamma table should be used. This is generally the
> > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> > index f1affc1bb679..6c3324f60e7d 100644
> > --- a/drivers/gpu/drm/drm_mode_config.c
> > +++ b/drivers/gpu/drm/drm_mode_config.c
> > @@ -364,6 +364,20 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
> >                 return -ENOMEM;
> >         dev->mode_config.gamma_lut_size_property = prop;
> >
> > +       prop = drm_property_create(dev,
> > +                       DRM_MODE_PROP_BLOB,
> > +                       "CUBIC_LUT", 0);
> > +       if (!prop)
> > +               return -ENOMEM;
> > +       dev->mode_config.cubic_lut_property = prop;
> > +
> > +       prop = drm_property_create_range(dev,
> > +                       DRM_MODE_PROP_IMMUTABLE,
> > +                       "CUBIC_LUT_SIZE", 0, UINT_MAX);
> > +       if (!prop)
> > +               return -ENOMEM;
> > +       dev->mode_config.cubic_lut_size_property = prop;
> > +
> >         prop = drm_property_create(dev,
> >                                    DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_BLOB,
> >                                    "IN_FORMATS", 0);
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 5f43d64d2a07..df5cc2239adb 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -288,6 +288,15 @@ struct drm_crtc_state {
> >          */
> >         struct drm_property_blob *gamma_lut;
> >
> > +       /**
> > +        * @cubic_lut:
> > +        *
> > +        * Cubic Lookup table for converting pixel data. See
> > +        * drm_crtc_enable_color_mgmt(). The blob (if not NULL) is a 3D array
> > +        * of &struct drm_color_lut.
> > +        */
> > +       struct drm_property_blob *cubic_lut;
> > +
> >         /**
> >          * @target_vblank:
> >          *
> > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> > index ab424ddd7665..8edb0094e5a7 100644
> > --- a/include/drm/drm_mode_config.h
> > +++ b/include/drm/drm_mode_config.h
> > @@ -800,6 +800,17 @@ struct drm_mode_config {
> >          */
> >         struct drm_property *gamma_lut_size_property;
> >
> > +       /**
> > +        * @cubic_lut_property: Optional CRTC property to set the 3D LUT used to
> > +        * convert color spaces.
> > +        */
> > +       struct drm_property *cubic_lut_property;
> > +       /**
> > +        * @cubic_lut_size_property: Optional CRTC property for the size of the
> > +        * 3D LUT as supported by the driver (read-only).
> > +        */
> > +       struct drm_property *cubic_lut_size_property;
> > +
> >         /**
> >          * @suggested_x_property: Optional connector property with a hint for
> >          * the position of the output on the host's screen.

-- 
Regards,

Laurent Pinchart


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