"Rafael J. Wysocki" <rjw@xxxxxxx> writes: > On Tuesday, November 23, 2010, Alan Stern wrote: >> On Tue, 23 Nov 2010, Rafael J. Wysocki wrote: >> >> > > > Moreover, I'm not sure if we need an "IRQ safe" version of _idle. Why do >> > > > we need it, exactly? >> > > >> > > Because pm_runtime_put_sync() calls rpm_idle(). If there were no >> > > irq-safe version of rpm_idle() then drivers wouldn't be able to call >> > > pm_runtime_put_sync() from within an interrupt handler. >> > >> > Right. Which they can't do now, can they? >> >> True. That was the point of this patch -- to allow interrupt handlers >> to do runtime PM, which they can't do now. > > The original idea was to allow suspend and resume to be carried out > with interrupts off, not necessarily by interrupt handlers. We've never > considered doing that with _idle before. > >> > Why do you think we should allow them to do that? >> >> Are you suggesting that interrupt handlers stick to pm_runtime_suspend >> and pm_runtime_resume, and ignore pm_runtime_get_sync and >> pm_runtime_put_sync? > > Why do they need the _sync versions? What exactly is wrong with > calling > > pm_runtime_put_noidle() > pm_runtime_suspend() > > from an interrupt handler if it really wants the synchronous suspend to be > carried out at this point? > > I don't really see a reason for calling pm_runtime_put_sync() by an interrupt > handler, but perhaps I'm overlooking something important. While I like the idea of the symmetry of having both _get_sync() and _put_sync() callable from an interrupt handler, I can't currently think of a situation where we would need to _put_sync() in the ISR. A standard _put() should suffice for all cases I can imagine. Kevin _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
