Re: [RFC PATCH 05/40] drm/amd/display: add shaper LUT driver-private props

[Harry Wentland <harry.wentland@amd.com>]

On 4/23/23 10:10, Melissa Wen wrote:
> CRTC shaper LUT shapes the content after blending, i.e., de-linearizes
> or normalizes space before applying a 3D LUT color correction. In the
> next patch, we add CRTC 3D LUT property to DRM color management after
> this shaper LUT and before the current CRTC gamma LUT.
> 

It might be good to describe the motivation behind the "de-linearization"
of pixels. Since a 3DLUT has a limited number of entries in each dimension
we want to use them in an optimal fashion. This means using the 3DLUT in
a colorspace that is optimized for human vision, such as sRGB, PQ, or
another non-linear space.

> Signed-off-by: Melissa Wen <mwen@igalia.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_display.c   |  28 ++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h      |  14 ++
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  17 +++
>  .../amd/display/amdgpu_dm/amdgpu_dm_crtc.c    | 122 +++++++++++++++++-
>  4 files changed, 179 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> index 8632ab695a6c..44c22cb87dde 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
> @@ -1247,6 +1247,30 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
>  	return &amdgpu_fb->base;
>  }
>  
> +#ifdef CONFIG_STEAM_DECK

Something like AMD_PRIVATE_COLOR would be better.

It might also be enough to guard only the bits that make the uAPI
appear, such as drm_property_create, etc.

Harry

> +static int
> +amdgpu_display_create_color_properties(struct amdgpu_device *adev)
> +{
> +	struct drm_property *prop;
> +
> +	prop = drm_property_create(adev_to_drm(adev),
> +				   DRM_MODE_PROP_BLOB,
> +				   "AMD_SHAPER_LUT", 0);
> +	if (!prop)
> +		return -ENOMEM;
> +	adev->mode_info.shaper_lut_property = prop;
> +
> +	prop = drm_property_create_range(adev_to_drm(adev),
> +					 DRM_MODE_PROP_IMMUTABLE,
> +					 "AMD_SHAPER_LUT_SIZE", 0, UINT_MAX);
> +	if (!prop)
> +		return -ENOMEM;
> +	adev->mode_info.shaper_lut_size_property = prop;
> +
> +	return 0;
> +}
> +#endif
> +
>  const struct drm_mode_config_funcs amdgpu_mode_funcs = {
>  	.fb_create = amdgpu_display_user_framebuffer_create,
>  };
> @@ -1323,6 +1347,10 @@ int amdgpu_display_modeset_create_props(struct amdgpu_device *adev)
>  			return -ENOMEM;
>  	}
>  
> +#ifdef CONFIG_STEAM_DECK
> +	if (amdgpu_display_create_color_properties(adev))
> +		return -ENOMEM;
> +#endif
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> index b8633df418d4..1fd3497af3b5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> @@ -344,6 +344,20 @@ struct amdgpu_mode_info {
>  	int			disp_priority;
>  	const struct amdgpu_display_funcs *funcs;
>  	const enum drm_plane_type *plane_type;
> +
> +	/* Driver-private color mgmt props */
> +#ifdef CONFIG_STEAM_DECK
> +	/**
> +	 * @shaper_lut_property: CRTC property to set post-blending shaper LUT
> +	 * that converts content before 3D LUT gamma correction.
> +	 */
> +	struct drm_property *shaper_lut_property;
> +	/**
> +	 * @shaper_lut_size_property: CRTC property for the size of
> +	 * post-blending shaper LUT as supported by the driver (read-only).
> +	 */
> +	struct drm_property *shaper_lut_size_property;
> +#endif
>  };
>  
>  #define AMDGPU_MAX_BL_LEVEL 0xFF
> 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 2e2413fd73a4..de63455896cc 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -726,6 +726,23 @@ struct dm_crtc_state {
>  	struct dc_info_packet vrr_infopacket;
>  
>  	int abm_level;
> +
> +#ifdef CONFIG_STEAM_DECK
> +	/* AMD driver-private color mgmt pipeline
> +	 *
> +	 * DRM provides CRTC degamma/ctm/gamma color mgmt features, but AMD HW
> +	 * has a larger set of post-blending color calibration features, as
> +	 * below:
> +	 */
> +	/**
> +	 * @shaper_lut:
> +	 *
> +	 * Lookup table used to de-linearize pixel data for gamma correction.
> +	 * See drm_crtc_enable_color_mgmt(). The blob (if not NULL) is an array
> +	 * of &struct drm_color_lut.
> +	 */
> +	struct drm_property_blob *shaper_lut;
> +#endif
>  };
>  
>  #define to_dm_crtc_state(x) container_of(x, struct dm_crtc_state, base)
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> index e3762e806617..503433e5cb38 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> @@ -229,7 +229,9 @@ static void dm_crtc_destroy_state(struct drm_crtc *crtc,
>  	if (cur->stream)
>  		dc_stream_release(cur->stream);
>  
> -
> +#ifdef CONFIG_STEAM_DECK
> +	drm_property_blob_put(cur->shaper_lut);
> +#endif
>  	__drm_atomic_helper_crtc_destroy_state(state);
>  
>  
> @@ -266,7 +268,12 @@ static struct drm_crtc_state *dm_crtc_duplicate_state(struct drm_crtc *crtc)
>  	state->crc_skip_count = cur->crc_skip_count;
>  	state->mpo_requested = cur->mpo_requested;
>  	/* TODO Duplicate dc_stream after objects are stream object is flattened */
> +#ifdef CONFIG_STEAM_DECK
> +	state->shaper_lut = cur->shaper_lut;
>  
> +	if (state->shaper_lut)
> +		drm_property_blob_get(state->shaper_lut);
> +#endif
>  	return &state->base;
>  }
>  
> @@ -299,6 +306,111 @@ static int amdgpu_dm_crtc_late_register(struct drm_crtc *crtc)
>  }
>  #endif
>  
> +#ifdef CONFIG_STEAM_DECK
> +/**
> + * drm_crtc_additional_color_mgmt - enable additional color properties
> + * @crtc: DRM CRTC
> + *
> + * This function lets the driver enable the 3D LUT color correction property
> + * on a CRTC. This includes shaper LUT, 3D LUT and regamma TF. The shaper
> + * LUT and 3D LUT property is only attached if its size is not 0.
> + */
> +static void
> +dm_crtc_additional_color_mgmt(struct drm_crtc *crtc)
> +{
> +	struct amdgpu_device *adev = drm_to_adev(crtc->dev);
> +
> +	if (adev->dm.dc->caps.color.mpc.num_3dluts) {
> +		drm_object_attach_property(&crtc->base,
> +					   adev->mode_info.shaper_lut_property, 0);
> +		drm_object_attach_property(&crtc->base,
> +					   adev->mode_info.shaper_lut_size_property,
> +					   MAX_COLOR_LUT_ENTRIES);
> +	}
> +}
> +
> +static int
> +atomic_replace_property_blob_from_id(struct drm_device *dev,
> +					 struct drm_property_blob **blob,
> +					 uint64_t blob_id,
> +					 ssize_t expected_size,
> +					 ssize_t expected_elem_size,
> +					 bool *replaced)
> +{
> +	struct drm_property_blob *new_blob = NULL;
> +
> +	if (blob_id != 0) {
> +		new_blob = drm_property_lookup_blob(dev, blob_id);
> +		if (new_blob == NULL)
> +			return -EINVAL;
> +
> +		if (expected_size > 0 &&
> +		    new_blob->length != expected_size) {
> +			drm_property_blob_put(new_blob);
> +			return -EINVAL;
> +		}
> +		if (expected_elem_size > 0 &&
> +		    new_blob->length % expected_elem_size != 0) {
> +			drm_property_blob_put(new_blob);
> +			return -EINVAL;
> +		}
> +	}
> +
> +	*replaced |= drm_property_replace_blob(blob, new_blob);
> +	drm_property_blob_put(new_blob);
> +
> +	return 0;
> +}
> +
> +static int
> +amdgpu_dm_atomic_crtc_set_property(struct drm_crtc *crtc,
> +				   struct drm_crtc_state *state,
> +				   struct drm_property *property,
> +				   uint64_t val)
> +{
> +	struct amdgpu_device *adev = drm_to_adev(crtc->dev);
> +	struct dm_crtc_state *acrtc_state = to_dm_crtc_state(state);
> +	bool replaced = false;
> +	int ret;
> +
> +	if (property == adev->mode_info.shaper_lut_property) {
> +		ret = atomic_replace_property_blob_from_id(crtc->dev,
> +					&acrtc_state->shaper_lut,
> +					val,
> +					-1, sizeof(struct drm_color_lut),
> +					&replaced);
> +		acrtc_state->base.color_mgmt_changed |= replaced;
> +		return ret;
> +	} else {
> +		drm_dbg_atomic(crtc->dev,
> +			       "[CRTC:%d:%s] unknown property [PROP:%d:%s]]\n",
> +			       crtc->base.id, crtc->name,
> +			       property->base.id, property->name);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +amdgpu_dm_atomic_crtc_get_property(struct drm_crtc *crtc,
> +				   const struct drm_crtc_state *state,
> +				   struct drm_property *property,
> +				   uint64_t *val)
> +{
> +	struct amdgpu_device *adev = drm_to_adev(crtc->dev);
> +	struct dm_crtc_state *acrtc_state = to_dm_crtc_state(state);
> +
> +	if (property == adev->mode_info.shaper_lut_property)
> +		*val = (acrtc_state->shaper_lut) ?
> +			acrtc_state->shaper_lut->base.id : 0;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +#endif
> +
>  /* Implemented only the options currently available for the driver */
>  static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs = {
>  	.reset = dm_crtc_reset_state,
> @@ -317,6 +429,10 @@ static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs = {
>  #if defined(CONFIG_DEBUG_FS)
>  	.late_register = amdgpu_dm_crtc_late_register,
>  #endif
> +#ifdef CONFIG_STEAM_DECK
> +	.atomic_set_property = amdgpu_dm_atomic_crtc_set_property,
> +	.atomic_get_property = amdgpu_dm_atomic_crtc_get_property,
> +#endif
>  };
>  
>  static void dm_crtc_helper_disable(struct drm_crtc *crtc)
> @@ -477,9 +593,11 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
>  	is_dcn = dm->adev->dm.dc->caps.color.dpp.dcn_arch;
>  	drm_crtc_enable_color_mgmt(&acrtc->base, is_dcn ? MAX_COLOR_LUT_ENTRIES : 0,
>  				   true, MAX_COLOR_LUT_ENTRIES);
> -
>  	drm_mode_crtc_set_gamma_size(&acrtc->base, MAX_COLOR_LEGACY_LUT_ENTRIES);
>  
> +#ifdef CONFIG_STEAM_DECK
> +	dm_crtc_additional_color_mgmt(&acrtc->base);
> +#endif
>  	return 0;
>  
>  fail: