[Intel-gfx] [PATCH 03/13] drm/i915: Precompute gamma_mode

[Shankar, Uma]

>-----Original Message-----
>From: Roper, Matthew D
>Sent: Saturday, January 12, 2019 6:12 AM
>To: Ville Syrjala <ville.syrjala at linux.intel.com>
>Cc: intel-gfx at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>
>Subject: Re: [PATCH 03/13] drm/i915: Precompute gamma_mode
>
>On Fri, Jan 11, 2019 at 07:08:13PM +0200, Ville Syrjala wrote:
>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>
>> We shouldn't be computing gamma mode during the commit phase.
>> Move it to the check phase.
>>
>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
>Looks like this also drops the posting reads, but I don't see anything in the bspec
>that indicates those were necessary in the first place.
>
>> ---
>>  drivers/gpu/drm/i915/intel_color.c | 44
>> +++++++++++++++++-------------
>>  1 file changed, 25 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_color.c
>> b/drivers/gpu/drm/i915/intel_color.c
>> index 37fd9ddf762e..b10e66ce3970 100644
>> --- a/drivers/gpu/drm/i915/intel_color.c
>> +++ b/drivers/gpu/drm/i915/intel_color.c
>> @@ -375,8 +375,7 @@ static void haswell_load_luts(struct intel_crtc_state
>*crtc_state)
>>  		reenable_ips = true;
>>  	}
>>
>> -	crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
>> -	I915_WRITE(GAMMA_MODE(crtc->pipe), GAMMA_MODE_MODE_8BIT);
>> +	I915_WRITE(GAMMA_MODE(crtc->pipe), crtc_state->gamma_mode);
>>
>>  	i9xx_load_luts(crtc_state);
>>
>> @@ -476,9 +475,7 @@ static void broadwell_load_luts(struct intel_crtc_state
>*crtc_state)
>>  	bdw_load_gamma_lut(crtc_state,
>>  			   INTEL_INFO(dev_priv)->color.degamma_lut_size);
>>
>> -	crtc_state->gamma_mode = GAMMA_MODE_MODE_SPLIT;
>> -	I915_WRITE(GAMMA_MODE(pipe), GAMMA_MODE_MODE_SPLIT);
>> -	POSTING_READ(GAMMA_MODE(pipe));
>> +	I915_WRITE(GAMMA_MODE(pipe), crtc_state->gamma_mode);
>>
>>  	/*
>>  	 * Reset the index, otherwise it prevents the legacy palette to be
>> @@ -532,9 +529,7 @@ static void glk_load_luts(struct intel_crtc_state
>> *crtc_state)
>>
>>  	bdw_load_gamma_lut(crtc_state, 0);
>>
>> -	crtc_state->gamma_mode = GAMMA_MODE_MODE_10BIT;
>> -	I915_WRITE(GAMMA_MODE(pipe), GAMMA_MODE_MODE_10BIT);
>> -	POSTING_READ(GAMMA_MODE(pipe));
>> +	I915_WRITE(GAMMA_MODE(pipe), crtc_state->gamma_mode);
>>  }
>>
>>  /* Loads the palette/gamma unit for the CRTC on CherryView. */ @@
>> -608,29 +603,40 @@ void intel_color_load_luts(struct intel_crtc_state
>> *crtc_state)  int intel_color_check(struct intel_crtc_state
>> *crtc_state)  {
>>  	struct drm_i915_private *dev_priv =
>> to_i915(crtc_state->base.crtc->dev);
>> +	const struct drm_property_blob *gamma_lut = crtc_state-
>>base.gamma_lut;
>> +	const struct drm_property_blob *degamma_lut =
>> +crtc_state->base.degamma_lut;
>>  	size_t gamma_length, degamma_length;
>>
>>  	degamma_length = INTEL_INFO(dev_priv)->color.degamma_lut_size;
>>  	gamma_length = INTEL_INFO(dev_priv)->color.gamma_lut_size;
>>
>>  	/*
>> -	 * We allow both degamma & gamma luts at the right size or
>> -	 * NULL.
>> +	 * We also allow no degamma lut/ctm and a gamma lut at the legacy
>> +	 * size (256 entries).
>>  	 */
>
>Minor nit:  now that the order of tests is swapped, you probably want to move
>the "also" from this comment down to the one below.
>
>Otherwise,
>
>Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

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

>
>> -	if ((!crtc_state->base.degamma_lut ||
>> -	     drm_color_lut_size(crtc_state->base.degamma_lut) ==
>degamma_length) &&
>> -	    (!crtc_state->base.gamma_lut ||
>> -	     drm_color_lut_size(crtc_state->base.gamma_lut) == gamma_length))
>> +	if (crtc_state_is_legacy_gamma(crtc_state)) {
>> +		crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
>>  		return 0;
>> +	}
>>
>>  	/*
>> -	 * We also allow no degamma lut/ctm and a gamma lut at the legacy
>> -	 * size (256 entries).
>> +	 * We allow both degamma & gamma luts at the right size or
>> +	 * NULL.
>>  	 */
>> -	if (crtc_state_is_legacy_gamma(crtc_state))
>> -		return 0;
>> +	if (degamma_lut && drm_color_lut_size(degamma_lut) !=
>degamma_length)
>> +		return -EINVAL;
>> +
>> +	if (gamma_lut && drm_color_lut_size(gamma_lut) != gamma_length)
>> +		return -EINVAL;
>> +
>> +	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
>> +		crtc_state->gamma_mode = GAMMA_MODE_MODE_10BIT;
>> +	else if (INTEL_GEN(dev_priv) >= 9 || IS_BROADWELL(dev_priv))
>> +		crtc_state->gamma_mode = GAMMA_MODE_MODE_SPLIT;
>> +	else
>> +		crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
>>
>> -	return -EINVAL;
>> +	return 0;
>>  }
>>
>>  void intel_color_init(struct intel_crtc *crtc)
>> --
>> 2.19.2
>>
>
>--
>Matt Roper
>Graphics Software Engineer
>IoTG Platform Enabling & Development
>Intel Corporation
>(916) 356-2795