Re: [Qemu-devel] [PATCH] hw/char/cmsdk-apb-timer: Correctly identify and set one-shot mode

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Jul 02, 2018 at 06:10:36PM +0100, Peter Maydell wrote:
> On 2 July 2018 at 18:05, Guenter Roeck <linux@roeck-us.net> wrote:
> > I don't think I'll have more time available to spend on this
> > anytime soon. If it works for you, just drop the patch. I can
> > keep it local in my branch. My version of qemu is different anyway,
> > after all.
> 
> I'd kind of like to fix the bug, though. I'd just like you
> to provide the image you're testing with...
> 

Ah, but that won't help. We are dealing with a heisenbug, and me using
a different host than you (or even a different gcc version) may be
sufficient to make the problem disappear on your system.

The mps2 images use high resolution timers, which is likely what is
triggering here. My working assumption is that those timers trigger at
the wrong time because the timer is set up in periodic instead of one-time
mode. With that, behavior is more or less random. On some systems it will
work, on some systems it won't. Since we can not agree that setting the
timer in periodic mode instead of one-shot mode is a problem, I don't
really see how we can proceed. I would somehow have to prove to you that
there is an observable problem in the first place, well beyond of what
I already did. That might take a lot of time - much more than I would
be able to spend on it.

Guenter