[PREEMPT_RT PATCH 0/3] i915 fixups for lockdep/lockdebugging

From: Clark Williams
Date: Mon Aug 19 2019 - 20:33:31 EST


From: Clark Williams <williams@xxxxxxxxxx>

The i915 driver was throwing splats on my home test box running
v5.2-rt3 when I turned on lockdep and lock debugging configs. This was
mainly due to the non-side effects of the spin*_irq*() macros which do
nothing to IRQs on PREEMPT_RT. Converting the various irq_lock spinlocks
and the uncore lock to be raw_spinlock_t fixes this, although I'm not
sure of the performance implications for latency spikes.

Testing was done on an Intel NUC with the following graphics:

00:02.0 VGA compatible controller: Intel Corporation Iris Plus Graphics 650 (rev 06)

Testing on other variants of i915 would be appreciated.

Clark Williams (3):
i915: do not call lockdep_assert_irqs_disabled() on PREEMPT_RT
i915: convert all irq_locks spinlocks to raw spinlocks
i915: convert uncore lock to raw spinlock

drivers/gpu/drm/i915/i915_debugfs.c | 8 +-
drivers/gpu/drm/i915/i915_drv.c | 6 +-
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/i915_gem.c | 4 +-
drivers/gpu/drm/i915/i915_irq.c | 154 ++++++++++-----------
drivers/gpu/drm/i915/i915_pmu.c | 4 +-
drivers/gpu/drm/i915/intel_breadcrumbs.c | 51 +++----
drivers/gpu/drm/i915/intel_display.c | 20 +--
drivers/gpu/drm/i915/intel_engine_cs.c | 4 +-
drivers/gpu/drm/i915/intel_engine_types.h | 2 +-
drivers/gpu/drm/i915/intel_fifo_underrun.c | 16 +--
drivers/gpu/drm/i915/intel_guc.c | 6 +-
drivers/gpu/drm/i915/intel_guc.h | 10 +-
drivers/gpu/drm/i915/intel_hotplug.c | 36 ++---
drivers/gpu/drm/i915/intel_pm.c | 8 +-
drivers/gpu/drm/i915/intel_runtime_pm.c | 8 +-
drivers/gpu/drm/i915/intel_sprite.c | 32 ++---
drivers/gpu/drm/i915/intel_tv.c | 8 +-
drivers/gpu/drm/i915/intel_uncore.c | 52 +++----
drivers/gpu/drm/i915/intel_uncore.h | 2 +-
drivers/gpu/drm/i915/intel_workarounds.c | 4 +-
21 files changed, 220 insertions(+), 217 deletions(-)

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2.21.0