Re: [v5][PATCH 11/11] drm/i915: Add intel_color_lut_equal() to compare hw and sw gamma/degamma lut values

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

On Sat, May 04, 2019 at 10:41:40PM +0530, Swati Sharma wrote:
> v3: Rebase
> v4: -Renamed intel_compare_color_lut() to intel_color_lut_equal() [Jani]
>     -Added the default label above the correct label [Jani]
>     -Corrected smatch warn "variable dereferenced before check" [Dan Carpenter]
> v5: -Added condition (!blob1 && !blob2) return true [Jani]
>     -Called PIPE_CONF_CHECK_COLOR_LUT inside if (!adjust) [Jani]
>     -Added #undef PIPE_CONF_CHECK_COLOR_LUT [Jani]
> 
> There are few things wrong in this patch:
> [1] For chv bit precision is 14, on what basis it should be assigned?

Like everything else it will more or less be a reverse of the
compute side. For CHV we need to look at cgm_mode, gamma_enable,
gamma_mode, and c8_planes. Hmm. We actually don't have readout for
c8_planes so I guess we'll have to make some kind of exception for
that one.

> [2] For glk and icl, degamma LUT values are not rounded off, there
> should err=0 if using same function, how to make that exception?

You mean the degamma? Just set precision==16? Maybe I'm not
understanding the question.

> [3] For glk, bit precision is 10 but gamma mode is 8BIT?

Not sure what you mean. glk gamma_mode works just like with
other ilk+ platforms (apart from not having the csc_mode
gamma vs. degamma control).

I suspect the most annoying case is ivb-bdw 10bit gamma mode
since we probably don't have the full readout to do the reverse
mapping of whether the LUT is used as gamma or degamma. But I
guess we'll just have to compare it against whichever one the
software state has.

> 
> Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_color.c   | 54 ++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_color.h   |  6 ++++
>  drivers/gpu/drm/i915/intel_display.c | 12 ++++++++
>  3 files changed, 72 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
> index 695b76d..73cb901 100644
> --- a/drivers/gpu/drm/i915/intel_color.c
> +++ b/drivers/gpu/drm/i915/intel_color.c
> @@ -1630,6 +1630,60 @@ static void ilk_read_luts(struct intel_crtc_state *crtc_state)
>  		crtc_state->base.gamma_lut = ilk_read_gamma_lut(crtc_state);
>  }
>  
> +static inline bool err_check(struct drm_color_lut *sw_lut, struct drm_color_lut *hw_lut, u32 err)
> +{
> +	 return ((abs((long)hw_lut->red - sw_lut->red)) <= err) &&
> +	        ((abs((long)hw_lut->blue - sw_lut->blue)) <= err) &&
> +	        ((abs((long)hw_lut->green - sw_lut->green)) <= err);
> +}
> +
> +bool intel_color_lut_equal(struct drm_property_blob *blob1,
> +			   struct drm_property_blob *blob2,
> +			   u32 gamma_mode)
> +{
> +	struct drm_color_lut *sw_lut, *hw_lut;
> +	int sw_lut_size, hw_lut_size, i;
> +	u32 bit_precision, err;
> +
> +	if (!blob1 && !blob2)
> +		return true;
> +
> +	if (!blob1 || !blob2)
> +		return false;
> +
> +	sw_lut_size = drm_color_lut_size(blob1);
> +	hw_lut_size = drm_color_lut_size(blob2);
> +
> +	if (sw_lut_size != hw_lut_size)
> +		return false;
> +
> +	switch(gamma_mode) {
> +	default:
> +	case GAMMA_MODE_MODE_8BIT:
> +		bit_precision = 8;
> +		break;
> +	case GAMMA_MODE_MODE_10BIT:
> +	case GAMMA_MODE_MODE_SPLIT:
> +		bit_precision = 10;
> +		break;
> +	case GAMMA_MODE_MODE_12BIT:
> +		bit_precision = 12;
> +		break;
> +	}
> +
> +	sw_lut = blob1->data;
> +	hw_lut = blob2->data;
> +
> +	err = 0xffff >> bit_precision;
> +
> +	for (i = 0; i < sw_lut_size; i++) {
> +		 if (!err_check(&hw_lut[i], &sw_lut[i], err))
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
>  void intel_color_init(struct intel_crtc *crtc)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> diff --git a/drivers/gpu/drm/i915/intel_color.h b/drivers/gpu/drm/i915/intel_color.h
> index fc53de9..b525c80 100644
> --- a/drivers/gpu/drm/i915/intel_color.h
> +++ b/drivers/gpu/drm/i915/intel_color.h
> @@ -6,13 +6,19 @@
>  #ifndef __INTEL_COLOR_H__
>  #define __INTEL_COLOR_H__
>  
> +#include <linux/types.h>
> +
>  struct intel_crtc_state;
>  struct intel_crtc;
> +struct drm_property_blob;
>  
>  void intel_color_init(struct intel_crtc *crtc);
>  int intel_color_check(struct intel_crtc_state *crtc_state);
>  void intel_color_commit(const struct intel_crtc_state *crtc_state);
>  void intel_color_load_luts(const struct intel_crtc_state *crtc_state);
>  void intel_color_read_luts(struct intel_crtc_state *crtc_state);
> +bool intel_color_lut_equal(struct drm_property_blob *blob1,
> +				 struct drm_property_blob *blob2,
> +				 u32 gamma_mode);
>  
>  #endif /* __INTEL_COLOR_H__ */
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 791974b..a713171 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12287,6 +12287,14 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>  	} \
>  } while (0)
>  
> +#define PIPE_CONF_CHECK_COLOR_LUT(name, gamma_mode) do { \
> +	if (!intel_color_lut_equal(current_config->name, pipe_config->name, gamma_mode)) { \
> +		pipe_config_err(adjust, __stringify(name), \
> +				"hw_state doesn't match sw_state\n"); \
> +		ret = false; \
> +	} \
> +} while (0)
> +
>  #define PIPE_CONF_QUIRK(quirk) \
>  	((current_config->quirks | pipe_config->quirks) & (quirk))
>  
> @@ -12376,6 +12384,9 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>  			PIPE_CONF_CHECK_X(csc_mode);
>  		PIPE_CONF_CHECK_BOOL(gamma_enable);
>  		PIPE_CONF_CHECK_BOOL(csc_enable);
> +
> +		PIPE_CONF_CHECK_COLOR_LUT(base.gamma_lut, pipe_config->gamma_mode);
> +		PIPE_CONF_CHECK_COLOR_LUT(base.degamma_lut, pipe_config->gamma_mode);
>  	}
>  
>  	PIPE_CONF_CHECK_BOOL(double_wide);
> @@ -12438,6 +12449,7 @@ static bool fastboot_enabled(struct drm_i915_private *dev_priv)
>  #undef PIPE_CONF_CHECK_FLAGS
>  #undef PIPE_CONF_CHECK_CLOCK_FUZZY
>  #undef PIPE_CONF_QUIRK
> +#undef PIPE_CONF_CHECK_COLOR_LUT
>  
>  	return ret;
>  }
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel
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