diff options
Diffstat (limited to 'debian/patches-rt/0003-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch')
| -rw-r--r-- | debian/patches-rt/0003-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/debian/patches-rt/0003-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch b/debian/patches-rt/0003-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch new file mode 100644 index 0000000000..583f8e96c9 --- /dev/null +++ b/debian/patches-rt/0003-drm-i915-Don-t-check-for-atomic-context-on-PREEMPT_R.patch @@ -0,0 +1,39 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Mon, 25 Oct 2021 15:05:18 +0200 +Subject: [PATCH 3/8] drm/i915: Don't check for atomic context on PREEMPT_RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz + +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> +--- + drivers/gpu/drm/i915/i915_utils.h | 9 +++++++-- + 1 file changed, 7 insertions(+), 2 deletions(-) + +--- a/drivers/gpu/drm/i915/i915_utils.h ++++ b/drivers/gpu/drm/i915/i915_utils.h +@@ -273,8 +273,13 @@ wait_remaining_ms_from_jiffies(unsigned + (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 defined(CONFIG_DRM_I915_DEBUG) && defined(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 defined(CONFIG_DRM_I915_DEBUG) && defined(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) |