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

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Message-Id: <20190820003319.24135-1-clark.williams@gmail.com>
Date:   Mon, 19 Aug 2019 19:33:16 -0500
From:   Clark Williams <clark.williams@...il.com>
To:     bigeasy@...utronix.com
Cc:     tglx@...utronix.com, linux-rt-users@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PREEMPT_RT PATCH 0/3] i915 fixups for lockdep/lockdebugging

From: Clark Williams <williams@...hat.com>

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(-)

-- 
2.21.0