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* [PATCH] drm/i915/dp: Fix potential infinite loop in 128b/132b SST
@ 2025-02-04 15:49 Jani Nikula
  2025-02-04 15:52 ` Imre Deak
                   ` (8 more replies)
  0 siblings, 9 replies; 11+ messages in thread
From: Jani Nikula @ 2025-02-04 15:49 UTC (permalink / raw)
  To: intel-gfx, intel-xe; +Cc: jani.nikula, Imre Deak

Passing 0 as the step only works when there are other reasons to break
out of the BPP loop in intel_dp_mtp_tu_compute_config(). Otherwise, an
infinite loop might occur. Fix it by explicitly checking for 0 step.

Fixes: ef0a0757bbea ("drm/i915/dp: compute config for 128b/132b SST w/o DSC")
Reported-by: Imre Deak <imre.deak@intel.com>
Closes: https://lore.kernel.org/r/Z6I0knh2Kt5T0JrT@ideak-desk.fi.intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

---

Note: This needs a backport with (!step) for -rc1.
---
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 95abc6ea85eb..1587be5cd0a7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -353,6 +353,10 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp,
 
 			break;
 		}
+
+		/* Allow using zero step to indicate one try */
+		if (!bpp_step_x16)
+			break;
 	}
 
 	if (slots < 0) {
-- 
2.39.5


^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2025-02-05 13:41 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
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2025-02-04 15:49 [PATCH] drm/i915/dp: Fix potential infinite loop in 128b/132b SST Jani Nikula
2025-02-04 15:52 ` Imre Deak
2025-02-05 13:41   ` Jani Nikula
2025-02-04 21:05 ` ✓ CI.Patch_applied: success for " Patchwork
2025-02-04 21:05 ` ✓ CI.checkpatch: " Patchwork
2025-02-04 21:06 ` ✓ CI.KUnit: " Patchwork
2025-02-04 21:23 ` ✓ CI.Build: " Patchwork
2025-02-04 21:25 ` ✓ CI.Hooks: " Patchwork
2025-02-04 21:26 ` ✓ CI.checksparse: " Patchwork
2025-02-04 21:45 ` ✓ Xe.CI.BAT: " Patchwork
2025-02-05  1:33 ` ✗ Xe.CI.Full: failure " Patchwork

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