On Wednesday, February 11, 2015 05:15:15 PM Boris Brezillon wrote: > On Wed, 11 Feb 2015 15:57:20 +0000 > Mark Rutland <mark.rutl...@arm.com> wrote: > > > [...] > > > > > > > > So for the flag at request time approach to work, all the drivers > > > > > > using > > > > > > the interrupt would have to flag they're safe in that context. > > > > > > > > > > Something like IRQF_"I can share the line with a timer" I guess? > > > > > That wouldn't > > > > > hurt and can be checked at request time even. > > > > > > > > I guess that would have to imply IRQF_SHARED, so we'd have something > > > > like: > > > > > > > > IRQF_SHARED_SUSPEND_OK - This handler is safe to call spuriously during > > > > suspend in the case the line is shared. The > > > > handler will not access unavailable hardware > > > > or kernel infrastructure during this period. > > > > > > > > #define __IRQF_SUSPEND_SPURIOUS 0x00040000 > > > > #define IRQF_SHARED_SUSPEND_OK (IRQF_SHARED | > > > > __IRQF_SUSPEND_SPURIOUS) > > > > > > What about > > > > > > #define __IRQF_TIMER_SIBLING_OK 0x00040000 > > > #define IRQF_SHARED_TIMER_OK (IRQF_SHARED | __IRQF_TIMER_SIBLING_OK) > > > > > > The "suspend" part is kind of a distraction to me here, because that > > > really > > > only is about sharing an IRQ with a timer and the "your interrupt handler > > > may be called when the device is suspended" part is just a consequence of > > > that. > > > > My rationale was that you didn't really care who else was using the IRQ > > (e.g. the timer); you're just stating that you can survive being called > > during suspend (which is what the driver may need to check for in the > > handler if the device happens to be powered down or whatever). > > > > So I guess I see it the other way around. This is essentially claiming > > we can handle sharing with IRQF_NO_SUSPEND rather than IRQF_TIMER. > > > > > So IMO it's better to have "TIMER" in the names to avoid encouraging > > > people to > > > abuse this for other purposes not related to timers. > > > > In the end a name is a name, and if you think IRQF_SHARED_TIMER_OK is > > better I shan't complain. > > > > The fundamental issue I'm concerned with is addressed by this approach. > > Okay then, is anyone taking care of submitting such a patch (Mark ?) ?
Well, I guess I should take the responsibility for that. :-) I'll try to cut one later today or tomorrow unless someone else beats me to that. Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
