On Wednesday 06 May 2009, Kevin Hilman wrote: > Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> writes: > > > "Rafael J. Wysocki" <rjw@xxxxxxx> writes: > > > >> On Wednesday 06 May 2009, Kevin Hilman wrote: > > [...] > > >>> > >>> [...] > >>> > >>> >>> > >>> >>> If this fixes some bug then please provide a description of that bug? > >>> >> > >>> >> The bug is that on TI OMAP, interrupts that are used for wakeup events > >>> >> are disabled by this code causing the system to no longer wake up. > >>> > > >>> > What do you do if the interrupt triggers right after your driver has > >>> > returned from its late suspend hook? > >>> > >>> If it's a wakeup IRQ, I assume you want it to prevent suspend. > >>> > >>> But I don't see how that can happen in the current code. IIUC, by the > >>> time your late suspend hook is run, your device IRQ is already > >>> disabled, so it won't trigger an interrupt that will be caught by > >>> check_wakeup_irqs() anyways. > >> > >> My understanding of __disable_irq() was that it didn't actually disable the > >> IRQ at the hardware level, allowing the CPU to actually receive the interrupt > >> and acknowledge it, but preventing the device driver for receiving it. > > > >> Does it work differently on the affected systems? > > > > Yes. > > > > __disable_irq() calls the irq_chip's disable method which is platform > > specific. On OMAP, this masks the IRQ at the hardware level > > preventing the CPU from seeing the interrupt. > > Looking at x86, the i8259 disable hook also seems to mask the IRQ at > the PIC level. > > The various IO-APIC irq_chips do not have a disable hook so the > __disable_irq() here is a NOP. Except that it sets IRQ_DISABLED. All right there. We can either avoid disabling wake-up interrupts, in which case we should drop check_wakeup_irqs() IMO, or rework things so that check_wakeup_irqs() will catch them. Doing both doesn't seem to make sense to me. Which one would be the right approach, then? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
