Re: [PATCH] x86, irq: Keep IRQ assignment for PCI devices during suspend/hibernation, bisected

[Borislav Petkov <bp@alien8.de>]

On Fri, Aug 01, 2014 at 08:27:23PM +0800, Jiang Liu wrote:
> 	The above commit may cause failure of suspend/hiberrnation.
> The reason is:
> 1) With recent changers, we dynamically allocate irq number for IOAPIC
>    pins.
> 2) The allocated irq will be released when suspending/hibernating.
> 	pci_disable_device()->pcibios_disable_irq()
> 3) When resuming, a different irq may be assigned to the PCI device.
> 	pci_enable_device()->pcibios_enable_irq()
> 4) Now the hardware will deliver interrupt to the new allocated irq
>    but the interrupt handler is still registered on old irq, so it
>    breaks the driver and causes failure of hibernation.
> 
> The patch sent out by me is to fix this issue by keeping the allocated
> irq when suspend/hibernate. And seems it works as expected.
> 
> But I still don't know why it causes IOMMU related warnings as:
> AMD-Vi: Event logged [IO_PAGE_FAULT device=00:12.0 domain=0x0009
> address=0x0000000000000000 flags=0x0000]

Well, the devices in those change during my test runs. Once it was
00:13.0, once this, once the GPU. This box has IOMMU so it might be
related to that somehow.

I could try to disable the IOMMU and see whether it still triggers. That
could tell us something.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--