"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. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
