Re: [3.9-rc1] irq 16: nobody cared (was [3.9-rc1] very poorinterrupt responses)

From: Peter Hurley
Date: Thu Mar 14 2013 - 13:27:29 EST


On Thu, 2013-03-14 at 18:22 +0100, Rafael J. Wysocki wrote:
> On Thursday, March 14, 2013 01:06:04 PM Peter Hurley wrote:
> > On Thu, 2013-03-14 at 17:46 +0100, Rafael J. Wysocki wrote:
> > > On Thursday, March 14, 2013 05:09:59 PM Jiri Kosina wrote:
> > > > On Thu, 14 Mar 2013, Jiri Kosina wrote:
> > > >
> > > > > > > I don't think I have seen this message on rc1+ (8343bce, to be precise),
> > > > > > > but I have definitely seen sluggish system response on that kernel as
> > > > > > > well.
> > > > > > >
> > > > > > > Attaching lspci, /proc/interrupts and dmesg.
> > > > > >
> > > > > > Can you try to do a git bisect for this? Is the sluggish system
> > > > > > response clear enough that you can tell reliably when it is present and
> > > > > > when it isn't?
> > > > >
> > > > > That was my first thought, but unfortunately I am afraid there will be
> > > > > point at which I will easily make a bisection mistake, as the
> > > > > responsiveness of the system varies over time, so it's not really a
> > > > > 100% objective measure.
> > > >
> > > > So I will try a bisect, but it'll take some time so that I could claim it
> > > > to be trustworthy.
> > > >
> > > > Therefore in case anyone has any idea in parallel, I am all ears.
> > >
> > > This one is a candidate to focus on I think:
> > >
> > > commit 181380b702eee1a9aca51354d7b87c7b08541fcf
> > > Author: Yinghai Lu <yinghai@xxxxxxxxxx>
> > > Date: Sat Feb 16 11:58:34 2013 -0700
> > >
> > > PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers
> >
> > This patch __fixed__ this problem for me in linux-next back in February.
> >
> > Rafael, did you hold back some ACPI patches from 3.9 that would have
> > made fix no longer applicable?
>
> No, I didn't.
>
> I'm afraid, though, that the fix might not be effective on some systems for a
> reason that's unclear at the moment.
>
> So in fact the one to check is commit 4f535093cf ("PCI: Put pci_dev in device
> tree as early as possible") and if the problem doesn't appear before that, we
> need to figure out why the fix may not be sufficient.

I agree.

Commit 4f535093cf ("PCI: Put pci_dev in device tree as early as
possible") is the likely culprit, and "Don't cache _PRT..." is probably
an insufficient fix.

Not so sure about the other reporters though because they had active
devices on those USB ports.

Regards,
Peter Hurley


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