[PATCH 05/17] drm/i915: Limit the output link bpp in DSC mode

[Imre Deak]

Limit the output link bpp in DSC mode to the link_config_limits
link.min_bpp .. max_bpp range the same way it's done in non-DSC mode.
Atm, this doesn't make a difference, the link bpp range being
0 .. max pipe bpp, but a follow-up patch will need a way to reduce max
link bpp below its current value.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c     | 12 +++++++++++-
 drivers/gpu/drm/i915/display/intel_dp_mst.c |  3 +++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index c4016fd0dc980..b5d38765dde54 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1703,9 +1703,16 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	pipe_config->lane_count = limits->max_lane_count;
 
 	if (intel_dp_is_edp(intel_dp)) {
+		u16 dsc_max_output_bpp;
+
+		dsc_max_output_bpp =
+			min_t(u16, drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd),
+			      limits->link.max_bpp);
+
 		pipe_config->dsc.compressed_bpp =
-			min_t(u16, drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd) >> 4,
+			min_t(u16, dsc_max_output_bpp >> 4,
 			      pipe_config->pipe_bpp);
+
 		pipe_config->dsc.slice_count =
 			drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
 							true);
@@ -1761,6 +1768,9 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 		 * calculation procedure is bit different for MST case.
 		 */
 		if (compute_pipe_bpp) {
+			dsc_max_output_bpp = min_t(u16, dsc_max_output_bpp,
+						   limits->link.max_bpp);
+
 			pipe_config->dsc.compressed_bpp = min_t(u16,
 								dsc_max_output_bpp >> 4,
 								pipe_config->pipe_bpp);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 48c247ddef53a..0dcb9a203dfe7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -230,6 +230,9 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
 	if (max_bpp > sink_max_bpp)
 		max_bpp = sink_max_bpp;
 
+	min_bpp = max(min_bpp, (limits->link.min_bpp + 0xf) >> 4);
+	max_bpp = min(max_bpp, limits->link.max_bpp >> 4);
+
 	slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state, max_bpp,
 						     min_bpp, limits,
 						     conn_state, 2 * 3, true);
-- 
2.37.2