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
