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* [i915-rt v6 00/24] drm/i915/display: All patches to make PREEMPT_RT work on i915 + xe.
@ 2026-02-20  8:36 Maarten Lankhorst
  2026-02-20  8:36 ` [i915-rt v6 01/24] drm/vblank_work: Add methods to schedule vblank_work in 2 stages Maarten Lankhorst
                   ` (29 more replies)
  0 siblings, 30 replies; 48+ messages in thread
From: Maarten Lankhorst @ 2026-02-20  8:36 UTC (permalink / raw)
  To: intel-gfx, intel-xe; +Cc: linux-rt-devel, dri-devel, Maarten Lankhorst

New version, new approach!

A lot of the problems with PREEMPT_RT happen because of the current vblank
handling. The real solution is making it more deterministic.

After calling local_irq_disable(), all kinds of register reads/writes are
done until interrupts are enabled again, without any lock used at all.

Patch 1-10 fixes all code related to vblank handling.
Patch 11-14 fixes all accidental locking in the atomic commit path.
Patch 15 is a standalone fix for interrupts, will probably push if xe results are clean.
Patch 16-20 fix problems in i915 specific driver code.
Patch 21, 23 and 24 are broken, but silences i915 in CI, should not be upstreamed.
Finally, patch 22 enables PREEMPT_RT on i915 too.

There are still failures on CI because of the uncore lock being problematic.

Still, I hope this series makes both the PREEMPT_RT devs and intel/display
folk equally (un)happy with this sequence:

local_irq_disable()
bunch of timing sensitive register writes without a single lock
local_irq_enable()

Maarten Lankhorst (19):
  drm/vblank_work: Add methods to schedule vblank_work in 2 stages
  drm/vblank: Add a 2-stage version of drm_crtc_arm_vblank_event
  drm/intel/display: Make intel_crtc_arm_vblank_event static
  drm/intel/display: Convert vblank event handling to 2-stage arming
  drm/i915/display: Move vblank put until after critical section
  drm/i915/display: Remove locking from intel_vblank_evade critical
    section
  drm/i915/display: Handle vlv dsi workaround in scanline_in_safe_range
    too
  drm/i915/display: Make get_vblank_counter use intel_de_read_fw()
  drm/i915/display: Do not take uncore lock in i915_get_vblank_counter
  drm/i915/display: Make icl_dsi_frame_update use _fw too
  drm/i915/display: Use intel_de_read/write_fw in colorops
  drm/i915/display: Use intel_de_write_fw in intel_pipe_fastset
  drm/i915/display: Make set_pipeconf use the fw variants
  drm/i915/display: Fix intel_lpe_audio_irq_handler for PREEMPT-RT
  drm/i915/gt: Fix selftests on PREEMPT_RT
  drm/i915/gt: Set stop_timeout() correctly on PREEMPT-RT
  drm/i915/display: Remove uncore lock from vlv_atomic_update_fifo
  PREEMPT_RT injection
  FOR-CI: bump MAX_STACK_TRACE_ENTRIES

Mike Galbraith (1):
  drm/i915: Use preempt_disable/enable_rt() where recommended

Sebastian Andrzej Siewior (4):
  drm/i915/gt: Use spin_lock_irq() instead of local_irq_disable() +
    spin_lock()
  drm/i915: Drop the irqs_disabled() check
  drm/i915/guc: Consider also RCU depth in busy loop.
  Revert "drm/i915: Depend on !PREEMPT_RT."

 drivers/gpu/drm/drm_vblank.c                  |  61 +++++++++-
 drivers/gpu/drm/drm_vblank_work.c             | 106 ++++++++++++----
 drivers/gpu/drm/i915/Kconfig                  |   1 -
 drivers/gpu/drm/i915/Kconfig.debug            |  15 ---
 drivers/gpu/drm/i915/display/i9xx_wm.c        |   4 -
 drivers/gpu/drm/i915/display/icl_dsi.c        |   4 +-
 drivers/gpu/drm/i915/display/intel_color.c    |   6 +-
 drivers/gpu/drm/i915/display/intel_crtc.c     |  86 ++++++-------
 drivers/gpu/drm/i915/display/intel_crtc.h     |   1 -
 drivers/gpu/drm/i915/display/intel_cursor.c   |   8 +-
 drivers/gpu/drm/i915/display/intel_de.h       |   8 ++
 drivers/gpu/drm/i915/display/intel_display.c  |  46 +++----
 .../gpu/drm/i915/display/intel_lpe_audio.c    |   2 +-
 drivers/gpu/drm/i915/display/intel_vblank.c   | 115 ++++++++++--------
 drivers/gpu/drm/i915/display/intel_vblank.h   |   1 +
 drivers/gpu/drm/i915/display/intel_vrr.c      |  18 +--
 drivers/gpu/drm/i915/gt/intel_engine_cs.c     |   2 +-
 .../drm/i915/gt/intel_execlists_submission.c  |  17 +--
 drivers/gpu/drm/i915/gt/selftest_engine_pm.c  |   8 +-
 drivers/gpu/drm/i915/gt/uc/intel_guc.h        |   2 +-
 drivers/gpu/drm/i915/i915_request.c           |   2 -
 drivers/gpu/drm/i915/intel_uncore.h           |  26 ++--
 drivers/gpu/drm/xe/Kconfig.debug              |   5 +
 .../drm/xe/compat-i915-headers/intel_uncore.h |   7 ++
 include/drm/drm_vblank.h                      |  14 ++-
 include/drm/drm_vblank_work.h                 |  12 ++
 kernel/Kconfig.preempt                        |   4 +-
 lib/Kconfig.debug                             |   4 +-
 28 files changed, 376 insertions(+), 209 deletions(-)

-- 
2.51.0


^ permalink raw reply	[flat|nested] 48+ messages in thread

end of thread, other threads:[~2026-03-05 11:19 UTC | newest]

Thread overview: 48+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-02-20  8:36 [i915-rt v6 00/24] drm/i915/display: All patches to make PREEMPT_RT work on i915 + xe Maarten Lankhorst
2026-02-20  8:36 ` [i915-rt v6 01/24] drm/vblank_work: Add methods to schedule vblank_work in 2 stages Maarten Lankhorst
2026-02-20 12:24   ` [i915-rt v6.1 1/1] " Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 02/24] drm/vblank: Add a 2-stage version of drm_crtc_arm_vblank_event Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 03/24] drm/intel/display: Make intel_crtc_arm_vblank_event static Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 04/24] drm/intel/display: Convert vblank event handling to 2-stage arming Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 05/24] drm/i915/display: Move vblank put until after critical section Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 06/24] drm/i915/display: Remove locking from intel_vblank_evade " Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 07/24] drm/i915/display: Handle vlv dsi workaround in scanline_in_safe_range too Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 08/24] drm/i915: Use preempt_disable/enable_rt() where recommended Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 09/24] drm/i915/display: Make get_vblank_counter use intel_de_read_fw() Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 10/24] drm/i915/display: Do not take uncore lock in i915_get_vblank_counter Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 11/24] drm/i915/display: Make icl_dsi_frame_update use _fw too Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 12/24] drm/i915/display: Use intel_de_read/write_fw in colorops Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 13/24] drm/i915/display: Use intel_de_write_fw in intel_pipe_fastset Maarten Lankhorst
2026-02-25  9:25   ` Jani Nikula
2026-02-25 11:59     ` Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 14/24] drm/i915/display: Make set_pipeconf use the fw variants Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 15/24] drm/i915/display: Fix intel_lpe_audio_irq_handler for PREEMPT-RT Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 16/24] drm/i915/gt: Use spin_lock_irq() instead of local_irq_disable() + spin_lock() Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 17/24] drm/i915: Drop the irqs_disabled() check Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 18/24] drm/i915/guc: Consider also RCU depth in busy loop Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 19/24] drm/i915/gt: Fix selftests on PREEMPT_RT Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 20/24] drm/i915/gt: Set stop_timeout() correctly on PREEMPT-RT Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 21/24] drm/i915/display: Remove uncore lock from vlv_atomic_update_fifo Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 22/24] Revert "drm/i915: Depend on !PREEMPT_RT." Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 23/24] PREEMPT_RT injection Maarten Lankhorst
2026-02-20  8:37 ` [i915-rt v6 24/24] FOR-CI: bump MAX_STACK_TRACE_ENTRIES Maarten Lankhorst
2026-02-24 14:15   ` Sebastian Andrzej Siewior
2026-02-25 12:32     ` Maarten Lankhorst
2026-02-20  8:46 ` ✗ CI.checkpatch: warning for drm/i915/display: All patches to make PREEMPT_RT work on i915 + xe. (rev12) Patchwork
2026-02-20  8:48 ` ✓ CI.KUnit: success " Patchwork
2026-02-20  9:04 ` ✗ CI.checksparse: warning " Patchwork
2026-02-20  9:38 ` ✓ Xe.CI.BAT: success " Patchwork
2026-02-20 21:03 ` ✗ Xe.CI.FULL: failure " Patchwork
2026-02-24 16:27 ` [i915-rt v6 00/24] drm/i915/display: All patches to make PREEMPT_RT work on i915 + xe Sebastian Andrzej Siewior
2026-02-24 16:59   ` Sebastian Andrzej Siewior
2026-02-25  7:58     ` Sebastian Andrzej Siewior
2026-02-25 12:15       ` Maarten Lankhorst
2026-02-25 20:06       ` Maarten Lankhorst
2026-02-26 12:07         ` Sebastian Andrzej Siewior
2026-02-26 14:19           ` Sebastian Andrzej Siewior
2026-02-26 14:38             ` Sebastian Andrzej Siewior
2026-03-05 10:19               ` Maarten Lankhorst
2026-03-05 10:42               ` Maarten Lankhorst
2026-03-05 10:50                 ` Sebastian Andrzej Siewior
2026-03-05 11:11                   ` Maarten Lankhorst
2026-03-05 11:19                     ` Sebastian Andrzej Siewior

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