Re: [PATCH 1/1] ahci: Do not receive interrupts sent by dummy ports

[David Milburn]

On 04/17/2014 12:06 PM, Tejun Heo wrote:
> On Thu, Apr 17, 2014 at 06:06:15PM +0200, Alexander Gordeev wrote:
> > In multiple MSI mode all AHCI ports (including dummy) get
> > assigned separate MSI vectors and (as result of execution
> > pci_enable_msi_exact() function) separate IRQ numbers,
> > (mapped to the MSI vectors).
> >
> > Therefore, although interrupts from dummy ports are not
> > desired they are still enabled. We do not request IRQs
> > for dummy ports, but that only means we do not assign
> > AHCI-specific ISRs to corresponding IRQ numbers.
> >
> > As result, dummy port interrupts still could come and
> > traverse all the way from the PCI device to the kernel,
> > causing unnecessary overhead.
> >
> > This update disables IRQs for dummy ports and prevents
> > the described issue.
> >
> > Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
> > Cc: Tejun Heo <tj@xxxxxxxxxx>
> > Cc: David Milburn <dmilburn@xxxxxxxxxx>
> > Cc: linux-ide@xxxxxxxxxxxxxxx
>
> David, can you please test the patch?


Hi,

I have re-tested successfully, this patch prevents the crash
when using kdump, and I boot tested a system that boots off
ahci and has dummy ports present, no problems seen.

Thanks,
David


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