Re: [PATCH 01/10] drm/i915: Extract check_luts()

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

On Wed, Mar 20, 2019 at 08:14:56AM -0700, Matt Roper wrote:
> On Wed, Mar 20, 2019 at 04:41:31PM +0200, Ville Syrjälä wrote:
> > On Tue, Mar 19, 2019 at 02:59:38PM -0700, Matt Roper wrote:
> > > On Mon, Mar 18, 2019 at 06:13:08PM +0200, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > 
> > > > In prepartion for per-platform color_check() functions extract the
> > > > common code into a separate function.
> > > > 
> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_color.c | 68 ++++++++++++++++++------------
> > > >  1 file changed, 40 insertions(+), 28 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
> > > > index 467fd1a1630c..b6a992a5b14f 100644
> > > > --- a/drivers/gpu/drm/i915/intel_color.c
> > > > +++ b/drivers/gpu/drm/i915/intel_color.c
> > > > @@ -771,6 +771,38 @@ static int check_lut_size(const struct drm_property_blob *lut, int expected)
> > > >  	return 0;
> > > >  }
> > > >  
> > > > +static int check_luts(const 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;
> > > > +	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 needs the legacy LUT all to itself */
> > > > +	if (crtc_state->c8_planes)
> > > > +		return -EINVAL;
> > > 
> > > Do we need to test for non-NULL gamma_lut here?
> > 
> > For c8? We already checked crtc_state_is_legacy_gamma() above.
> > 
> 
> If gamma_lut == NULL, crtc_state_is_legacy_gamma() will return false, so
> we'll wind up rejecting any setup involving c8 planes with -EINVAL,
> which I don't think is what we wanted.

I think it is. c8 scanout always uses the legacy LUT, so it had 
better be populated with the correct data or else we'll risk
producing garbage on the display.

> 
> 
> Matt
> 
> 
> > > 
> > > The logic is the same as before your patch, so either we already had a
> > > pre-existing bug or, more likely, I'm overlooking something obvious.
> > > 
> > > > +
> > > > +	degamma_length = INTEL_INFO(dev_priv)->color.degamma_lut_size;
> > > > +	gamma_length = INTEL_INFO(dev_priv)->color.gamma_lut_size;
> > > > +	degamma_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
> > > > +	gamma_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
> > > > +
> > > > +	if (check_lut_size(degamma_lut, degamma_length) ||
> > > > +	    check_lut_size(gamma_lut, gamma_length))
> > > > +		return -EINVAL;
> > > > +
> > > > +	if (drm_color_lut_check(degamma_lut, degamma_tests) ||
> > > > +	    drm_color_lut_check(gamma_lut, gamma_tests))
> > > > +		return -EINVAL;
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > >  static u32 chv_cgm_mode(const struct intel_crtc_state *crtc_state)
> > > >  {
> > > >  	u32 cgm_mode = 0;
> > > > @@ -794,19 +826,11 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
> > > >  	const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
> > > >  	const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;
> > > >  	bool limited_color_range = false;
> > > > -	int gamma_length, degamma_length;
> > > > -	u32 gamma_tests, degamma_tests;
> > > >  	int ret;
> > > >  
> > > > -	degamma_length = INTEL_INFO(dev_priv)->color.degamma_lut_size;
> > > > -	gamma_length = INTEL_INFO(dev_priv)->color.gamma_lut_size;
> > > > -	degamma_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
> > > > -	gamma_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
> > > > -
> > > > -	/* C8 needs the legacy LUT all to itself */
> > > > -	if (crtc_state->c8_planes &&
> > > > -	    !crtc_state_is_legacy_gamma(crtc_state))
> > > > -		return -EINVAL;
> > > > +	ret = check_luts(crtc_state);
> > > > +	if (ret)
> > > > +		return ret;
> > > >  
> > > >  	crtc_state->gamma_enable = (gamma_lut || degamma_lut) &&
> > > >  		!crtc_state->c8_planes;
> > > > @@ -828,25 +852,10 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
> > > >  	if (IS_CHERRYVIEW(dev_priv))
> > > >  		crtc_state->cgm_mode = chv_cgm_mode(crtc_state);
> > > >  
> > > > -	/* Always allow legacy gamma LUT with no further checking. */
> > > >  	if (!crtc_state->gamma_enable ||
> > > > -	    crtc_state_is_legacy_gamma(crtc_state)) {
> > > > +	    crtc_state_is_legacy_gamma(crtc_state))
> > > >  		crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
> > > > -		if (INTEL_GEN(dev_priv) >= 11 &&
> > > > -		    crtc_state->gamma_enable)
> > > > -			crtc_state->gamma_mode |= POST_CSC_GAMMA_ENABLE;
> > > > -		return 0;
> > > > -	}
> > > > -
> > > > -	if (check_lut_size(degamma_lut, degamma_length) ||
> > > > -	    check_lut_size(gamma_lut, gamma_length))
> > > > -		return -EINVAL;
> > > > -
> > > > -	if (drm_color_lut_check(degamma_lut, degamma_tests) ||
> > > > -	    drm_color_lut_check(gamma_lut, gamma_tests))
> > > > -		return -EINVAL;
> > > > -
> > > > -	if (INTEL_GEN(dev_priv) >= 11)
> > > > +	else if (INTEL_GEN(dev_priv) >= 11)
> > > >  		crtc_state->gamma_mode = GAMMA_MODE_MODE_10BIT |
> > > >  					 PRE_CSC_GAMMA_ENABLE |
> > > >  					 POST_CSC_GAMMA_ENABLE;
> > > 
> > > Should we drop the GAMMA_ENABLE here and just rely on the new check
> > > you're adding below to handle it?
> > 
> > This will get rewritten entirely in following patches, so I figured I'd
> > just keep this patch minimal.
> > 
> > > 
> > > 
> > > Matt
> > > 
> > > > @@ -858,6 +867,9 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
> > > >  		crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;
> > > >  
> > > >  	if (INTEL_GEN(dev_priv) >= 11) {
> > > > +		if (crtc_state->gamma_enable)
> > > > +			crtc_state->gamma_mode |= POST_CSC_GAMMA_ENABLE;
> > > > +
> > > >  		if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
> > > >  		    crtc_state->limited_color_range)
> > > >  			crtc_state->csc_mode |= ICL_OUTPUT_CSC_ENABLE;
> > > > -- 
> > > > 2.19.2
> > > > 
> > > 
> > > -- 
> > > Matt Roper
> > > Graphics Software Engineer
> > > IoTG Platform Enabling & Development
> > > Intel Corporation
> > > (916) 356-2795
> > 
> > -- 
> > Ville Syrjälä
> > Intel
> 
> -- 
> Matt Roper
> Graphics Software Engineer
> IoTG Platform Enabling & Development
> Intel Corporation
> (916) 356-2795

-- 
Ville Syrjälä
Intel
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