Intel-XE Archive on lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] drm/i915/dp: Limit max compressed bpp to 18 when forcing DSC
@ 2024-10-30  8:41 Ankit Nautiyal
  2024-10-30  8:43 ` ✓ CI.Patch_applied: success for " Patchwork
                   ` (9 more replies)
  0 siblings, 10 replies; 12+ messages in thread
From: Ankit Nautiyal @ 2024-10-30  8:41 UTC (permalink / raw)
  To: intel-gfx; +Cc: intel-xe

While forcing DSC when it is not actually required, the max compressed
bpp from the source gets picked for compression for some pipe bpps.
Apparently, when DSC is not required, forcing DSC to the maximum compressed
bpp seems to cause underruns.

To avoid this, limit the max compressed bpp to 18 while forcing DSC. This
value works across platforms with different pipe bpps and prevents
underruns.

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

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 28fa5e2d0c33..0ce29cefaa13 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2021,6 +2021,15 @@ static int dsc_src_max_compressed_bpp(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
+	/*
+	 * Forcing DSC and using the platform's max compressed bpp is seen to cause
+	 * underruns. Since DSC isn't needed in these cases, limit the
+	 * max compressed bpp to 18, which is a safe value across platforms with different
+	 * pipe bpps.
+	 */
+	if (intel_dp->force_dsc_en)
+		return 18;
+
 	/*
 	 * Max Compressed bpp for Gen 13+ is 27bpp.
 	 * For earlier platform is 23bpp. (Bspec:49259).
-- 
2.45.2


^ permalink raw reply related	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2024-11-13  8:52 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-10-30  8:41 [PATCH] drm/i915/dp: Limit max compressed bpp to 18 when forcing DSC Ankit Nautiyal
2024-10-30  8:43 ` ✓ CI.Patch_applied: success for " Patchwork
2024-10-30  8:43 ` ✓ CI.checkpatch: " Patchwork
2024-10-30  8:45 ` ✓ CI.KUnit: " Patchwork
2024-10-30  8:56 ` ✓ CI.Build: " Patchwork
2024-10-30  8:58 ` ✓ CI.Hooks: " Patchwork
2024-10-30  9:00 ` ✗ CI.checksparse: warning " Patchwork
2024-10-30  9:26 ` ✓ CI.BAT: success " Patchwork
2024-10-30 10:21 ` ✗ CI.FULL: failure " Patchwork
2024-11-11  6:06 ` [PATCH] " Srikanth V, NagaVenkata
2024-11-11  6:55 ` Srikanth V, NagaVenkata
2024-11-13  8:52   ` Nautiyal, Ankit K

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox