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drm/i915/gt: use a LOCAL_IRQ_LOCK in __timeline_mark_lock() 

Quoting drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe

    We use a fake timeline->mutex lock to reassure lockdep that the timeline
    is always locked when emitting requests. However, the use inside
    __engine_park() may be inside hardirq and so lockdep now complains about
    the mixed irq-state of the nested locked. Disable irqs around the
    lockdep tracking to keep it happy.

This lockdep appeasement breaks RT because we take sleeping locks between
__timeline_mark_lock()/unlock().  Use a LOCAL_IRQ_LOCK instead.

Signed-off-by: Mike Galbraith <efaukt@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
This commit is contained in:
Mike Galbraith 2020-02-07 07:11:06 +01:00 committed by Alibek Omarov
parent 2896df71c2
commit 085e434453
1 changed files with 5 additions and 2 deletions
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7
drivers/gpu/drm/i915/gt/intel_engine_pm.c
View File

@ -38,12 +38,15 @@ static int __engine_unpark(struct intel_wakeref *wf)
}
#if IS_ENABLED(CONFIG_LOCKDEP)
#include <linux/locallock.h>
static DEFINE_LOCAL_IRQ_LOCK(timeline_lock);
static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
{
unsigned long flags;
local_irq_save(flags);
local_lock_irqsave(timeline_lock, flags);
mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
return flags;
@ -53,7 +56,7 @@ static inline void __timeline_mark_unlock(struct intel_context *ce,
unsigned long flags)
{
mutex_release(&ce->timeline->mutex.dep_map, 0, _THIS_IP_);
local_irq_restore(flags);
local_unlock_irqrestore(timeline_lock, flags);
}
#else