Re: Problem with commit bf22ff45bed664aefb5c4e43029057a199b7070c
From: Thomas Gleixner
Date: Wed Jul 12 2017 - 16:21:48 EST
On Wed, 12 Jul 2017, Thomas Gleixner wrote:
> On Mon, 10 Jul 2017, Juergen Gross wrote:
> > It is based on suspend/resume framework. The main work to be done
> > additionally is to disconnect from the pv-backends at save time and
> > connect to the pv-backends again at restore time.
> > The main function triggering all that is xen_suspend() (as seen in
> > above backtrace).
> The untested patch below should give you hooks to do what you need to do.
> Add the irq_suspend/resume callbacks and set the IRQCHIP_GENERIC_SUSPEND
> flag on your xen irqchip, so it actually gets invoked.
> I have to make that opt in right now because the callbacks are used in the
> generic irqchip implementation already. We can revisit that when you can
> confirm that this is actually solving the problem.
There might be an even simpler solution.
As this is using the regular suspend_device_irqs() call, you just might get
away with setting IRQCHIP_MASK_ON_SUSPEND for your irq chip. That does not
use the lazy disable approach, it also masks all interrupts which are not
marked as wakeup irqs. I assume none of them is when you do that
That said, you still might make the whole mechanism cleaner by using the
irq chip callbacks so you can avoid traversing all the interrupts another
time. But I can't say for sure as I got lost in that xen event channel code.