Messages in this thread |  | | Subject | Re: [ANNOUNCE] v5.4.17-rt9 | From | Fernando Lopez-Lezcano <> | Date | Thu, 6 Feb 2020 22:13:46 -0800 |
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On 2/6/20 10:11 PM, Mike Galbraith wrote: > 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.
Wow, Mike, thanks!, will try it out and report... (might take me a couple of days)
-- Fernando
> 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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