[PATCH v3 0/7] drm/i915: All fixes to make i915 work well with PREEMPT_RT.

[Maarten Lankhorst <dev@lankhorst.se>]

All fixes to make the core i915 module (without display) working correctly on
PREEMPT_RT.

Some fixes are still needed, as the selftests still fail. But otherwise the
test results were looking good on PREEMPT_RT.

It looks like the patch that added a spinlock caused a regression on !PREEMPT_RT,
and may even have caused similar test failures on PREEMPT_RT, so to fix it
I removed RCU entirely, and converted to a locked implementation instead.

This time at least, i915 live selftests pass on !PREEMPRT_RT for at least 1 machine
with same config as CI.

Changes since v2:
- Remove the extra signaler_active lock, it broke because
  it didn't protect anything, instead use signalers_lock.

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Maarten Lankhorst (3):
  drm/i915/gt: Fix selftests on PREEMPT_RT
  drm/i915/gt: Set stop_timeout() correctly on PREEMPT-RT
  drm/i915: Use sleeping selftests for igt_atomic on PREEMPT_RT

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.
  drm/i915/gt: Use signalers_lock to prevent starvation of irq_work.

 drivers/gpu/drm/i915/gt/intel_breadcrumbs.c   | 169 +++++++++++-------
 .../gpu/drm/i915/gt/intel_breadcrumbs_types.h |   1 -
 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/selftests/igt_atomic.c   |   7 +
 8 files changed, 127 insertions(+), 81 deletions(-)

-- 
2.53.0