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* [PATCH 0/2] Fix pipe fifo underruns during cdclk/DDB transitions
@ 2026-06-08 12:50 Nemesa Garg
  2026-06-08 12:50 ` [RFC PATCH 1/2] drm/i915/cdclk: Avoid VCO-change glitches Nemesa Garg
                   ` (4 more replies)
  0 siblings, 5 replies; 8+ messages in thread
From: Nemesa Garg @ 2026-06-08 12:50 UTC (permalink / raw)
  To: intel-gfx, intel-xe; +Cc: Nemesa Garg

	This series fixes two distinct classes of pipe FIFO underruns
observed during modesets and back-to-back atomic commits.

1. Patch 1 avoids cdclk VCO-change glitches in bxt_modeset_calc_cdclk()
by preferring a same-VCO table entry (pure squash, no DBUF ratio
change) over an intermediate that drops below min_cdclk or flips the
DBUF ratio mid-commit.

2. Patch 2 closes a brief DDB-overlap window when back-to-back commits
reshuffle per-plane PLANE_BUF_CFG sub-ranges without changing the per-pipe
DBUF allocation, MBUS join or slice mask. Shrinking ranges are pre-
programmed and a vblank is awaited so hw retires the old (larger) ranges
before grown/new planes occupy the freed space.

Nemesa Garg (2):
  drm/i915/cdclk: Avoid VCO-change glitches
  drm/i915/wm: wait a vblank before shrinking plane DDB

 drivers/gpu/drm/i915/display/intel_cdclk.c   | 47 +++++++++++++++++++
 drivers/gpu/drm/i915/display/skl_watermark.c | 49 ++++++++++++++++++++
 2 files changed, 96 insertions(+)

-- 
2.25.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2026-06-08 21:38 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-06-08 12:50 [PATCH 0/2] Fix pipe fifo underruns during cdclk/DDB transitions Nemesa Garg
2026-06-08 12:50 ` [RFC PATCH 1/2] drm/i915/cdclk: Avoid VCO-change glitches Nemesa Garg
2026-06-08 13:11   ` Ville Syrjälä
2026-06-08 12:50 ` [RFC PATCH 2/2] drm/i915/wm: Wait a vblank before shrinking plane DDB Nemesa Garg
2026-06-08 13:14   ` Ville Syrjälä
2026-06-08 13:27 ` ✓ CI.KUnit: success for Fix pipe fifo underruns during cdclk/DDB transitions Patchwork
2026-06-08 17:27 ` ✓ i915.CI.BAT: " Patchwork
2026-06-08 21:38 ` ✗ i915.CI.Full: failure " Patchwork

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