Messages in this thread Patch in this message |  | | Subject | Re: [ANNOUNCE] v5.4.17-rt9 | From | Mike Galbraith <> | Date | Fri, 07 Feb 2020 07:11:06 +0100 |
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On Thu, 2020-02-06 at 15:59 -0800, Fernando Lopez-Lezcano wrote: > On 2/4/20 8:58 AM, Sebastian Andrzej Siewior wrote: > > Dear RT folks! > > > > I'm pleased to announce the v5.4.17-rt9 patch set. > > Thanks! > I see a continuous stream of these:
(snips gripage)
Yup, d67739268cf0 annoys RT locking if lockdep is enabled. The below shut it up for my i915 equipped lappy.
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> --- drivers/gpu/drm/i915/gt/intel_engine_pm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -38,12 +38,15 @@ static int __engine_unpark(struct intel_ }
#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_unloc unsigned long flags) { mutex_release(&ce->timeline->mutex.dep_map, 0, _THIS_IP_); - local_irq_restore(flags); + local_unlock_irqrestore(timeline_lock, flags); }
#else
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