[PATCH 21/26] drm/i915/dp: Add support for 3 vdsc engines and 12 slices.

[Ankit Nautiyal]

Certain resolutions require 12 DSC slices support along with ultrajoiner.
For such cases, the third VDSC Engine per Pipe is enabled. Each VDSC
Engine processes 1 Slice, resulting in a total of 12 VDSC Instances
(4 Pipes * 3 VDSC Instances per Pipe).
Add support for 12 DSC slices and 3 VDSC engines for such modes.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index bcea3e875579..9dde41c17b2f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -112,8 +112,10 @@ static const u8 valid_dsc_bpp[] = {6, 8, 10, 12, 15};
 
 /* With Single pipe configuration, HW is capable of supporting maximum
  * of 4 slices per line.
+ * For higher resolutions where 12 slice support is required with
+ * ultrajoiner, only then each pipe can support 3 slices.
  */
-static const u8 valid_dsc_slicecount[] = {1, 2, 4};
+static const u8 valid_dsc_slicecount[] = {1, 2, 3, 4};
 
 /**
  * intel_dp_is_edp - is the given port attached to an eDP panel (either CPU or PCH)
@@ -2465,8 +2467,13 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	 * VDSC engine operates at 1 Pixel per clock, so if peak pixel rate
 	 * is greater than the maximum Cdclock and if slice count is even
 	 * then we need to use 2 VDSC instances.
+	 * In case of Ultrajoiner along with 12 slices we need to use 3
+	 * VDSC instances.
 	 */
-	if (pipe_config->joiner_pipes || pipe_config->dsc.slice_count > 1)
+	if (pipe_config->joiner_pipes && joined_pipes == 4 &&
+	    pipe_config->dsc.slice_count == 12)
+		pipe_config->dsc.dsc_split = DSC_SPLIT_3_STREAMS;
+	else if (pipe_config->joiner_pipes || pipe_config->dsc.slice_count > 1)
 		pipe_config->dsc.dsc_split = DSC_SPLIT_2_STREAMS;
 
 	ret = intel_dp_dsc_compute_params(connector, pipe_config);
-- 
2.45.2