[Intel-gfx] [PATCH v3 16/20] drm/i915: Rework legacy LUT handling

Shankar, Uma uma.shankar at intel.com
Fri Nov 18 18:17:58 UTC 2022



> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville Syrjala
> Sent: Monday, November 14, 2022 9:07 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v3 16/20] drm/i915: Rework legacy LUT handling
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Currently crtc_state_is_legacy_gamma() has a very specific set of conditions, not all
> of which are actually necessary. Also Also when we detect those conditions

Nit: "Also" duplicated.

Looks Good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> check_luts() just skips all the checks. That will no longer work for glk soon when we'll
> start to use the hw degamma LUT in place of the hw gamma LUT for YCbCr output.
> So let's rework the logic to only really consider whether the user provided
> gamma_lut is one that matches the hw legacy LUT capabilities or not.
> 
> We'll need to reject C8+degamma on ivb+ since the presence of degamma_lut would
> either mean we have to really use the LUT for degamma as opposed to C8 palette,
> or we have to enable split gamma mode which also can't work as the C8 palette.
> 
> Otherwise this will now cause the legacy LUT to go through the regular lut checks as
> well. As a side effect we also start to allow the use of the legacy LUT with CTM, but
> that is perfectly fine as far a the hardware is concerned.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_color.c | 82 +++++++++++++++-------
>  1 file changed, 55 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_color.c
> b/drivers/gpu/drm/i915/display/intel_color.c
> index e2bcfbffb298..8bb8983b490c 100644
> --- a/drivers/gpu/drm/i915/display/intel_color.c
> +++ b/drivers/gpu/drm/i915/display/intel_color.c
> @@ -154,15 +154,7 @@ static const u16 ilk_csc_postoff_rgb_to_ycbcr[3] = {
> 
>  static bool lut_is_legacy(const struct drm_property_blob *lut)  {
> -	return drm_color_lut_size(lut) == LEGACY_LUT_LENGTH;
> -}
> -
> -static bool crtc_state_is_legacy_gamma(const struct intel_crtc_state *crtc_state) -{
> -	return !crtc_state->hw.degamma_lut &&
> -		!crtc_state->hw.ctm &&
> -		crtc_state->hw.gamma_lut &&
> -		lut_is_legacy(crtc_state->hw.gamma_lut);
> +	return lut && drm_color_lut_size(lut) == LEGACY_LUT_LENGTH;
>  }
> 
>  /*
> @@ -1317,6 +1309,42 @@ intel_color_add_affected_planes(struct intel_crtc_state
> *new_crtc_state)
>  	return 0;
>  }
> 
> +static u32 intel_gamma_lut_tests(const struct intel_crtc_state
> +*crtc_state) {
> +	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> +	const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
> +
> +	if (lut_is_legacy(gamma_lut))
> +		return 0;
> +
> +	return INTEL_INFO(i915)->display.color.gamma_lut_tests;
> +}
> +
> +static u32 intel_degamma_lut_tests(const struct intel_crtc_state
> +*crtc_state) {
> +	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> +
> +	return INTEL_INFO(i915)->display.color.degamma_lut_tests;
> +}
> +
> +static int intel_gamma_lut_size(const struct intel_crtc_state
> +*crtc_state) {
> +	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> +	const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
> +
> +	if (lut_is_legacy(gamma_lut))
> +		return LEGACY_LUT_LENGTH;
> +
> +	return INTEL_INFO(i915)->display.color.gamma_lut_size;
> +}
> +
> +static u32 intel_degamma_lut_size(const struct intel_crtc_state
> +*crtc_state) {
> +	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> +
> +	return INTEL_INFO(i915)->display.color.degamma_lut_size;
> +}
> +
>  static int check_lut_size(const struct drm_property_blob *lut, int expected)  {
>  	int len;
> @@ -1342,21 +1370,17 @@ static int check_luts(const struct intel_crtc_state
> *crtc_state)
>  	int gamma_length, degamma_length;
>  	u32 gamma_tests, degamma_tests;
> 
> -	/* Always allow legacy gamma LUT with no further checking. */
> -	if (crtc_state_is_legacy_gamma(crtc_state))
> -		return 0;
> -
>  	/* C8 relies on its palette being stored in the legacy LUT */
> -	if (crtc_state->c8_planes) {
> +	if (crtc_state->c8_planes && !lut_is_legacy(crtc_state->hw.gamma_lut))
> +{
>  		drm_dbg_kms(&i915->drm,
>  			    "C8 pixelformat requires the legacy LUT\n");
>  		return -EINVAL;
>  	}
> 
> -	degamma_length = INTEL_INFO(i915)->display.color.degamma_lut_size;
> -	gamma_length = INTEL_INFO(i915)->display.color.gamma_lut_size;
> -	degamma_tests = INTEL_INFO(i915)->display.color.degamma_lut_tests;
> -	gamma_tests = INTEL_INFO(i915)->display.color.gamma_lut_tests;
> +	degamma_length = intel_degamma_lut_size(crtc_state);
> +	gamma_length = intel_gamma_lut_size(crtc_state);
> +	degamma_tests = intel_degamma_lut_tests(crtc_state);
> +	gamma_tests = intel_gamma_lut_tests(crtc_state);
> 
>  	if (check_lut_size(degamma_lut, degamma_length) ||
>  	    check_lut_size(gamma_lut, gamma_length)) @@ -1372,7 +1396,7 @@
> static int check_luts(const struct intel_crtc_state *crtc_state)  static u32
> i9xx_gamma_mode(struct intel_crtc_state *crtc_state)  {
>  	if (!crtc_state->gamma_enable ||
> -	    crtc_state_is_legacy_gamma(crtc_state))
> +	    lut_is_legacy(crtc_state->hw.gamma_lut))
>  		return GAMMA_MODE_MODE_8BIT;
>  	else
>  		return GAMMA_MODE_MODE_10BIT; /* i965+ only */ @@ -
> 1441,14 +1465,12 @@ static u32 chv_cgm_mode(const struct intel_crtc_state
> *crtc_state)  {
>  	u32 cgm_mode = 0;
> 
> -	if (crtc_state_is_legacy_gamma(crtc_state))
> -		return 0;
> -
>  	if (crtc_state->hw.degamma_lut)
>  		cgm_mode |= CGM_PIPE_MODE_DEGAMMA;
>  	if (crtc_state->hw.ctm)
>  		cgm_mode |= CGM_PIPE_MODE_CSC;
> -	if (crtc_state->hw.gamma_lut)
> +	if (crtc_state->hw.gamma_lut &&
> +	    !lut_is_legacy(crtc_state->hw.gamma_lut))
>  		cgm_mode |= CGM_PIPE_MODE_GAMMA;
> 
>  	return cgm_mode;
> @@ -1475,7 +1497,7 @@ static int chv_color_check(struct intel_crtc_state
> *crtc_state)
>  	 * Otherwise we bypass it and use the CGM gamma instead.
>  	 */
>  	crtc_state->gamma_enable =
> -		crtc_state_is_legacy_gamma(crtc_state) &&
> +		lut_is_legacy(crtc_state->hw.gamma_lut) &&
>  		!crtc_state->c8_planes;
> 
>  	crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT; @@ -1510,7
> +1532,7 @@ static bool ilk_csc_enable(const struct intel_crtc_state *crtc_state)
> static u32 ilk_gamma_mode(const struct intel_crtc_state *crtc_state)  {
>  	if (!crtc_state->gamma_enable ||
> -	    crtc_state_is_legacy_gamma(crtc_state))
> +	    lut_is_legacy(crtc_state->hw.gamma_lut))
>  		return GAMMA_MODE_MODE_8BIT;
>  	else
>  		return GAMMA_MODE_MODE_10BIT;
> @@ -1656,6 +1678,12 @@ static int ivb_color_check(struct intel_crtc_state
> *crtc_state)
>  	if (ret)
>  		return ret;
> 
> +	if (crtc_state->c8_planes && crtc_state->hw.degamma_lut) {
> +		drm_dbg_kms(&i915->drm,
> +			    "C8 pixelformat and degamma together are not
> possible\n");
> +		return -EINVAL;
> +	}
> +
>  	if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB &&
>  	    crtc_state->hw.ctm) {
>  		drm_dbg_kms(&i915->drm,
> @@ -1694,7 +1722,7 @@ static int ivb_color_check(struct intel_crtc_state
> *crtc_state)  static u32 glk_gamma_mode(const struct intel_crtc_state *crtc_state)
> {
>  	if (!crtc_state->gamma_enable ||
> -	    crtc_state_is_legacy_gamma(crtc_state))
> +	    lut_is_legacy(crtc_state->hw.gamma_lut))
>  		return GAMMA_MODE_MODE_8BIT;
>  	else
>  		return GAMMA_MODE_MODE_10BIT;
> @@ -1779,7 +1807,7 @@ static u32 icl_gamma_mode(const struct intel_crtc_state
> *crtc_state)
>  		gamma_mode |= POST_CSC_GAMMA_ENABLE;
> 
>  	if (!crtc_state->hw.gamma_lut ||
> -	    crtc_state_is_legacy_gamma(crtc_state))
> +	    lut_is_legacy(crtc_state->hw.gamma_lut))
>  		gamma_mode |= GAMMA_MODE_MODE_8BIT;
>  	/*
>  	 * Enable 10bit gamma for D13
> --
> 2.37.4



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