[PATCH 01/14] drm/i915/dp: Iterate DSC BPP from high to low on all platforms

[Jani Nikula <jani.nikula@intel.com>]

Commit 1c56e9a39833 ("drm/i915/dp: Get optimal link config to have best
compressed bpp") tries to find the best compressed bpp for the
link. However, it iterates from max to min bpp on display 13+, and from
min to max on other platforms. This presumably leads to minimum
compressed bpp always being chosen on display 11-12.

Iterate from high to low on all platforms to actually use the best
possible compressed bpp.

Fixes: 1c56e9a39833 ("drm/i915/dp: Get optimal link config to have best compressed bpp")
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: <stable@vger.kernel.org> # v6.7+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index d1b4fd542a1f..ecf192262eb9 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2073,11 +2073,10 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
 	/* Compressed BPP should be less than the Input DSC bpp */
 	dsc_max_bpp = min(dsc_max_bpp, output_bpp - 1);
 
-	for (i = 0; i < ARRAY_SIZE(valid_dsc_bpp); i++) {
-		if (valid_dsc_bpp[i] < dsc_min_bpp)
+	for (i = ARRAY_SIZE(valid_dsc_bpp) - 1; i >= 0; i--) {
+		if (valid_dsc_bpp[i] < dsc_min_bpp ||
+		    valid_dsc_bpp[i] > dsc_max_bpp)
 			continue;
-		if (valid_dsc_bpp[i] > dsc_max_bpp)
-			break;
 
 		ret = dsc_compute_link_config(intel_dp,
 					      pipe_config,
-- 
2.39.5