On Mon, Dec 01, 2014 at 06:50:43PM -0500, Lennart Sorensen wrote:
> On Tue, Dec 02, 2014 at 12:37:20AM +0100, Gilles Chanteperdrix wrote:
> > On Mon, Dec 01, 2014 at 06:35:54PM -0500, Lennart Sorensen wrote:
> > > On Mon, Dec 01, 2014 at 04:30:57PM +0100, Gilles Chanteperdrix wrote:
> > > > On the other hand, this is just a warning, it does not prevent the
> > > > system from working, and this warning warns us about a real problem:
> > > > we can not set the irq affinity of this driver.
> > >
> > > It was ugly and just a warning so I commented it out.
> > >
> > > I don't think the hardware has any way to do affinity, so it can't be
> > > fixed, so the warning doesn't help.
> >
> > Yes, but now you know it, without the message, you would not know it.
>
> True, but it sure looks terrible in the logs given it looks about the
> same as a kernel crash.
To the uninformed yes. Kernel bugs begin with "BUG", kernel faults
(which would be what is nearest from a kernel crash) begin with
"Unhandled fault in kernel mode". Not with "Warning:".
>
> And I still don't think there is anything that can be done about it.
> You can set the affinity of the GIC irq for the whole GPIO bank, but
> not for the individual pins of the gpio bank.
What I mean is that if you are writing a driver and you care about
irq latency, this information is important, it tells you can not pin
the irq handler to a particular core, and so that if you plan to
have a good latency, you should probably find an irq source which is
directly tied to the GIC, and avoid the GPIOs.
--
Gilles.
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