[PATCH v3 0/8] drm/i915: PREEMPT_RT related fixups.

Sebastian Andrzej Siewior bigeasy at linutronix.de
Fri Jun 28 12:57:59 UTC 2024


Hi,

The following patches are from the PREEMPT_RT queue.  It is mostly about
disabling interrupts/preemption which leads to problems. Unfortunately
DRM_I915_LOW_LEVEL_TRACEPOINTS had to be disabled because it acquires locks
from within trace points. Making the lock a raw_spinlock_t led to higher
latencies during video playback
  https://lore.kernel.org/all/20211006164628.s2mtsdd2jdbfyf7g@linutronix.de/

and I'm not sure if I hit the worse case here.
I tested it on a SandyBridge with built-in i915 by using X, OpenGL and
playing videos without noticing any warnings. However, some code paths
were not entered.
I carry them for some time now and most issues were reported by other
people and they reported that things work for them since.

v2…v3 https://lore.kernel.org/all/20240613102818.4056866-1-bigeasy@linutronix.de/
  - Collected tags.
  - Added comment to 3/8 explaining why RT is excluded from the test.
  
v1…v2:
  - The tracing disable bits (4/8) have been reworked after Steven pointed out
    that something isn't right.
  - The irq_work() bits have been dropped because they are no longer
    needed.


Sebastian


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