On Wed, 11 Feb 2015 16:32:31 +0000 Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Wed, Feb 11, 2015 at 04:15:15PM +0000, Boris Brezillon wrote: > > On Wed, 11 Feb 2015 15:57:20 +0000 > > Mark Rutland <mark.rutland@xxxxxxx> 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 ?) ? > > I'll have the core patch shortly. > > I'll need to ask for your help tagging the relevant drivers and testing. For the list of impacted drivers, you can have a look at this series [1] (patches 2 to 5), and I'll take care of the testing part once every one has agreed on the solution ;-). [1]https://lkml.org/lkml/2014/12/15/552 -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
