On Sat, May 23, 2009 at 7:29 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Saturday 23 May 2009, Kim Kyuwon wrote: >> On Sat, May 23, 2009 at 6:23 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: >> > On Friday 22 May 2009, Kim Kyuwon wrote: >> >> On Wed, May 6, 2009 at 8:27 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: >> >> > On Wednesday 06 May 2009, Kevin Hilman wrote: >> >> >> Arve Hjønnevåg <arve@xxxxxxxxxxx> writes: >> >> >> >> >> >> > On Tue, May 5, 2009 at 8:52 AM, Kevin Hilman >> >> >> > <khilman@xxxxxxxxxxxxxxxxxxx> wrote: >> >> >> >> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes: >> >> >> >> >> >> >> >>> On Mon, 4 May 2009 17:27:04 -0700 Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> wrote: >> >> >> >>> >> >> >> >>>> Interrupts that are flagged as wakeup sources via set_irq_wake() >> >> >> >>>> should not be disabled for suspend. >> >> >> >>>> >> >> >> >>> >> >> >> >>> Why not? >> >> >> >>> >> >> >> >> >> >> >> >> If an interrupt is a wakeup source, and it is disabled at the chip >> >> >> >> level, it will no longer generate interrupts, and thus no longer wake >> >> >> >> up the system. >> >> >> >> >> >> >> >> I'd be interested in hearing why wakeup interrupts should be disabled >> >> >> >> during suspend. >> >> > >> >> > That depends on whether or not they are used for anything else than wake-up. >> >> > >> >> >> >> >> >> [...] >> >> >> >> >> >> >>> >> >> >> >>> 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? >> >> >> >> Hi, Rafael. >> >> Sorry for bring the old issue but please let me ask you about >> >> suspend_device_irqs() function. >> >> >> >> __disable_irq() disables the IRQ at the hardware level in the >> >> following irq_chips >> >> >> >> i8259A_chip >> >> i8259_pic >> >> i8259A_chip >> >> bfin_internal_irqchip >> >> crisv10_irq_type >> >> crisv32_irq_type >> >> h8300irq_chip >> >> m_irq_chip >> >> mn10300_cpu_pic_level >> >> xtensa_irq_chip >> >> iop13xx_msi_chip >> >> msi_irq >> >> >> >> Because these irq_chips mask interrupts in 'disable' hook. >> >> >> >> Thus, your suspend_device_irqs() function disables all IRQs at the >> >> hardware level on all architectures which use irq_chips listed above >> >> in suspend state. >> >> Is this really what you wanted? >> > >> > What we wanted was to resolve specific issue related to the handling of >> > interrupts during suspend and resume which caused observable breakage and >> > from the point of view of fixing this issue it doesn't really matter whether or >> > not interrupts are masked in the disable hook. >> > >> >> If interrupt can wake up the system from suspend in some architectures >> >> and if disable_irq_wake is not supported in these architectures, I >> >> wonder if suspend_device_irqs() don't allow waking up by interrupt. >> > >> > I think that the platforms that may be affected by this issue will have to take >> > care of it. >> >> You changed the really important part of Linux, which may affect most >> processor architectures. I think you should be careful. If some of >> architectures can't take care of it (they can implement >> disable_irq_wake correctly in H/W level, will you revert your changes? > > No, the changes are not going to be reverted. In fact things should have been > done like this already much earlier. > > Now, do you have any particular example of a problem related to these changes > or is it only a theoretical issue? I'd CCing you when I'm sending a mail for this particular example of a example. http://markmail.org/thread/fvt7d62arofon5xx Regards, Kyuwon _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
