On Sat, May 23, 2009 at 6:25 AM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Friday 22 May 2009, Kim Kyuwon wrote: >> On Fri, May 22, 2009 at 11:53 AM, Kim Kyuwon <chammoru@xxxxxxxxx> 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? >> > >> > 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. >> > >> > Regards, >> > Kyuwon >> > >> >> I saw resume_device_irqs() is invoked after arch_suspend_enable_irqs() >> in your resume code. >> So in this gap between resume_device_irqs() and >> arch_suspend_enable_irqs(), a few interrupts would be discarded. >> i.e, a few data would be lost. >> >> If keypad wake up the system, first key pressed information would be lost. >> If I2C, USB, SPI, UART wake up the system, first a few data would be lost. >> >> Did you also consider this issue? > > I think it would happen anyway with the old code, wouldn't it? That's not quite right. For example, let's assume a keypad device is alive in suspend/resume state to wake up the system. Before arch_suspend_enable_irqs(), none of keypad irqs is dropped. It is just pending. But in your code, a few irqs are discarded due to your resume_device_irqs(). Regards, Kyuwon _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
