[Intel-gfx] [PATCH] drm/i915/dsc: Fix the usage of uncompressed bpp

[Vandita Kulkarni]

DP 1.4 spec limits max compression bpp to
uncompressed bpp -1, which is supported from
XELPD onwards.
Instead of uncompressed bpp, max dsc input bpp
was being used to limit the max compression bpp.

Fixes: 831d5aa96c97 ("drm/i915/xelpd: Support DP1.4 compression BPPs")
Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 9d8132dd4cc5..1f7e666ae490 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1322,7 +1322,7 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
 	const struct drm_display_mode *adjusted_mode =
 		&pipe_config->hw.adjusted_mode;
-	int pipe_bpp;
+	int pipe_bpp, max_dsc_pipe_bpp;
 	int ret;
 
 	pipe_config->fec_enable = !intel_dp_is_edp(intel_dp) &&
@@ -1331,7 +1331,8 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	if (!intel_dp_supports_dsc(intel_dp, pipe_config))
 		return -EINVAL;
 
-	pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state->max_requested_bpc);
+	pipe_bpp = pipe_config->pipe_bpp;
+	max_dsc_pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state->max_requested_bpc);
 
 	/* Min Input BPC for ICL+ is 8 */
 	if (pipe_bpp < 8 * 3) {
@@ -1345,7 +1346,7 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	 * Optimize this later for the minimum possible link rate/lane count
 	 * with DSC enabled for the requested mode.
 	 */
-	pipe_config->pipe_bpp = pipe_bpp;
+	pipe_config->pipe_bpp = max_dsc_pipe_bpp;
 	pipe_config->port_clock = limits->max_rate;
 	pipe_config->lane_count = limits->max_lane_count;
 
-- 
2.32.0