[Intel-gfx] [PATCH] drm/i915/icl: Fix checks for userspace ctm + ycbcr output

[Matt Roper]

We recently added support for gen11's new "output csc" which can be used
independently of the regular pipe CSC.  The idea is that this new output
csc allows us to use a userspace-provided color transformation matrix at
the same time we drive a YCBCR display mode requiring RGB->YUV
conversion.  However when landing that support we only updated the color
management code and overlooked that there was an additional atomic check
in the modeset path (in intel_crtc_compute_config()) that still assumes
we only have a single CSC unit to work with.  Let's update that check to
only apply to pre-gen11 platforms and move it into the color management
code to ensure it gets called on all commits, not just modesets.

Also, if we're *only* using the output CSC and not the pipe CSC, there's
no need to set crtc_state->csc_enable, so let's also not consider the
output format when setting csc_enable on gen11+ platforms.

Fixes: a91de580541c ("drm/i915/icl: Enable pipe output csc")
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
It might also be worth moving the full->limited range RGB conversion
from the pipe CSC to the output CSC on gen11 at some point.

 drivers/gpu/drm/i915/intel_color.c   | 16 +++++++++++++---
 drivers/gpu/drm/i915/intel_display.c | 12 ------------
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
index da7a07d5ccea..b47e6d1aaaec 100644
--- a/drivers/gpu/drm/i915/intel_color.c
+++ b/drivers/gpu/drm/i915/intel_color.c
@@ -780,9 +780,10 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
 	    IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
 		limited_color_range = crtc_state->limited_color_range;
 
-	crtc_state->csc_enable =
-		crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
-		crtc_state->base.ctm || limited_color_range;
+	crtc_state->csc_enable = crtc_state->base.ctm || limited_color_range;
+	if (INTEL_GEN(dev_priv) < 11)
+		crtc_state->csc_enable |=
+			crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB;
 
 	ret = intel_color_add_affected_planes(crtc_state);
 	if (ret)
@@ -822,6 +823,15 @@ int intel_color_check(struct intel_crtc_state *crtc_state)
 			crtc_state->csc_mode |= ICL_OUTPUT_CSC_ENABLE;
 
 		crtc_state->csc_mode |= ICL_CSC_ENABLE;
+	} else if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB &&
+		   crtc_state->base.ctm) {
+		/*
+		 * There is only one pipe CSC unit per pipe on pre-gen11, and
+		 * we need that for output conversion from RGB->YCBCR. So if
+		 * CTM is already applied we can't support YCBCR output.
+		 */
+		DRM_DEBUG_KMS("YCBCR420 and CTM together are not possible\n");
+		return -EINVAL;
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index afa21daaae51..81bfdbd99092 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6855,18 +6855,6 @@ static int intel_crtc_compute_config(struct intel_crtc *crtc,
 		return -EINVAL;
 	}
 
-	if ((pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR420 ||
-	     pipe_config->output_format == INTEL_OUTPUT_FORMAT_YCBCR444) &&
-	     pipe_config->base.ctm) {
-		/*
-		 * There is only one pipe CSC unit per pipe, and we need that
-		 * for output conversion from RGB->YCBCR. So if CTM is already
-		 * applied we can't support YCBCR420 output.
-		 */
-		DRM_DEBUG_KMS("YCBCR420 and CTM together are not possible\n");
-		return -EINVAL;
-	}
-
 	/*
 	 * Pipe horizontal size must be even in:
 	 * - DVO ganged mode
-- 
2.14.5