Hi Kieran,
On Mon, Dec 21, 2020 at 02:09:09PM +0000, Kieran Bingham wrote:
> On 21/12/2020 01:57, Laurent Pinchart wrote:
> > From: Kieran Bingham <kieran.bingham+rene...@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+rene...@ideasonboard.com>
> > Co-developed-by: Laurent Pinchart
> > <laurent.pinchart+rene...@ideasonboard.com>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
>
> Again, for the updates since I created the patch:
>
> Reviewed-by: Kieran Bingham <kieran.bingham+rene...@ideasonboard.com>
>
> A bit of a question on clarifying the added documentation but I don't
> think it's major.
>
> > ---
> > 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
>
> This sentence is a bit confusing. What bit depth is actually used, is it
> mandated to a specific subsampling? Or restricted to 8-bit....
We're both confused then, because I don't think I understand the
question :-)
> > + * 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.
>
> Is the table already reduced precision though ?
drm_color_lut has 16-bit precision. The precision of the table on the
hardware side varies.
> > + *
> > + * 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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