diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2025-07-14 17:39:48 +0200 |
|---|---|---|
| committer | Maarten Lankhorst <dev@lankhorst.se> | 2025-07-15 11:58:16 +0200 |
| commit | 8a643df55f3a9c034cf8d1942c25a6eb08d57d9d (patch) | |
| tree | 936c1d71d2ec415abb72c068b9815d98ace837f9 /drivers/gpu/drm/i915/i915_utils.h | |
| parent | bba9aa41654036534d86b198f5647a9ce15ebd7f (diff) | |
drm/i915: Don't check for atomic context on PREEMPT_RT
The !in_atomic() check in _wait_for_atomic() triggers on PREEMPT_RT
because the uncore::lock is a spinlock_t and does not disable
preemption or interrupts.
Changing the uncore:lock to a raw_spinlock_t doubles the worst case
latency on an otherwise idle testbox during testing.
Ignore _WAIT_FOR_ATOMIC_CHECK() on PREEMPT_RT.
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Link: https://lore.kernel.org/all/20211006164628.s2mtsdd2jdbfyf7g@linutronix.de/
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250714153954.629393-4-bigeasy@linutronix.de
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Diffstat (limited to 'drivers/gpu/drm/i915/i915_utils.h')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_utils.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index f7fb40cfdb70..9cb40c2c4b12 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -267,8 +267,13 @@ wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms) (Wmax)) #define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10, 1000) -/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */ -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) && IS_ENABLED(CONFIG_PREEMPT_COUNT) +/* + * If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. + * On PREEMPT_RT the context isn't becoming atomic because it is used in an + * interrupt handler or because a spinlock_t is acquired. This leads to + * warnings which don't occur otherwise and therefore the check is disabled. + */ +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) && IS_ENABLED(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT) # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) WARN_ON_ONCE((ATOMIC) && !in_atomic()) #else # define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) do { } while (0) |