On Friday, August 05, 2011, Kevin Hilman wrote: > "Rafael J. Wysocki" <rjw@xxxxxxx> writes: > > > On Friday, July 22, 2011, Kevin Hilman wrote: > >> Currently the use of pm_runtime_put_sync() is not safe from > >> interrupts-disabled context because rpm_idle() will release the > >> spinlock and enable interrupts for the idle callbacks. This enables > >> interrupts during a time where interrupts were expected to be > >> disabled, and can have strange side effects on drivers that expected > >> interrupts to be disabled. > >> > >> This is not a bug since the documentation clearly states that only > >> _put_sync_suspend() is safe in IRQ-safe mode. > >> > >> However, pm_runtime_put_sync() could be made safe when in IRQ-safe > >> mode by releasing the spinlock but not re-enabling interrupts, which > >> is what this patch aims to do. > >> > >> Problem was found when using some buggy drivers that set > >> pm_runtime_irq_safe() and used _put_sync() in interrupts-disabled > >> context. > >> > >> The offending drivers have been fixed to use _put_sync_suspend(), > >> But this patch is an RFC to see if it might make sense to allow > >> using _put_sync() from interrupts-disabled context. > > > > OK, I'm going to take this for 3.2. > > Rafael, > > Since you're planning to merge this, maybe we should consider merging > this as a fix for v3.1, and possibly even for v3.0 stable. That way, > any current drivers using irq_safe and the normal _put_sync() will not > have this problem. I think I can push it for 3.1, but I don't think it's stable material. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
