On Tuesday, July 29, 2014 03:33:23 PM Rafael J. Wysocki wrote: > On Tuesday, July 29, 2014 02:46:41 PM Thomas Gleixner wrote: > > On Tue, 29 Jul 2014, Rafael J. Wysocki wrote: > > > > > On Monday, July 28, 2014 11:53:15 PM Rafael J. Wysocki wrote: > > > > On Monday, July 28, 2014 02:33:41 PM Thomas Gleixner wrote: > > > > > On Mon, 28 Jul 2014, Peter Zijlstra wrote: > > > > > > On Sat, Jul 26, 2014 at 01:49:17PM +0200, Rafael J. Wysocki wrote: > > > > > > [cut] > > > > > > > > So we are not going to make everything a single stupid flag and limit > > > > > the usability of existing code. We rather go and try to remove the > > > > > stupid flag before it becomes more wide spread. > > > > > > > > > > And we cannot treat the wakeup thing the same way as the > > > > > IRQF_NO_SUSPEND flag, because there is hardware where the irq line > > > > > must be disabled at the normal (non suspend) interrupt controller, and > > > > > the wake mechanism tells the PM microcontroller to monitor the > > > > > interrupt line and kick the machine back to life. > > > > > > > > > > So we need to very carefully look at all the existing cases instead of > > > > > yelling crap and inflicting x86 specific horror on everyone. I said on > > > > > friday, that I need to look at ALL use cases first and I meant it. > > > > > > > > Regardless of the use case, I don't think it is necessary to manipulate > > > > the interrupt controller settings before the syscore_suspend stage, > > > > because > > > > if an interrupt happens earlier, we need to handle it pretty much in a > > > > normal > > > > way, unless it has been suspended. > > > > > > > > So I'd argue for not using anything like enable_irq_wake() that goes all > > > > the way to the hardware in drivers. Instead, we could allow drivers to > > > > mark interrupts as "set this up for system wakeup" and really do the > > > > setup > > > > right before putting the platform into the final "suspended" state. > > > > And that > > > > is totally independend of the IRQF_NO_SUSPEND thing. > > > > > > In addition to that we need the interrupt handler of the driver that > > > requested > > > the irq to be set up for system wakeup to be invoked after > > > suspend_device_irqs() > > > in case there are interrupts that should abort the suspend transition or > > > we > > > can lose a wakeup event. So whatever interface we decide to use it has to > > > affect suspend/resume_device_irqs() pretty much in the same way as the > > > IRQF_NO_SUSPEND flag. > > > > Right, that's a different issue. We probably want that even for the > > existing irq_wake() users. > > I agree. > > There's one more thing to consider here. Going forward we'll want to avoid > touching runtime-suspended devices during system suspend. Then, system wakeup > devices will need to mark their IRQs for system wakeup at the runtime suspend > time and I'm not sure if that's the right time for calling enable_irq_wake().
Taking all of the above into consideration I prepared a prototype that will follow. Patch [1/3] is the actual prototype of the core changes, patch [2/3] uses that to implement suspend-to-idle wakeup for PME and patch [3/3] illustrates how an existing user of enable_irq_wake() can be modified to use the new stuff. All is on top of https://patchwork.kernel.org/patch/4643871/ which should apply on top of -tip (if I'm not mistaken). I've tested patches [1-2/3] with PME on my MSI Wind. Comments welcome. 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/
