Re: ap4 (sh7372) regression in 3.3 / 3.4 with serial console - boot failures

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, May 22, 2012, Laurent Pinchart wrote:
> Hi Paul,
> 
> On Thursday 17 May 2012 09:46:04 Paul Mundt wrote:
> > On Wed, May 16, 2012 at 03:36:10PM +0200, Guennadi Liakhovetski wrote:
> > > I'm observing a regression with 3.3 and 3.4 kernels, 3.2 seems to be ok.
> > > The system (confirmed with mackerel and ap4evb) hangs during boot at
> > > random times. This can be directly after "freeing init memory," or some
> > > time during the OS start up, or immediately after the start up has
> > > completed. But if it managed to boot, it continues to run, I've never seen
> > > it hanging after I ssh onto the system. It also seems, that the
> > > probability to hang increases with time after the initial system power on.
> > > A simple short power off doesn't solve the problem.
> > 
> > So you experience random hangs at boot and you have a known good and
> > known bad version. If only there were some sort of a bisection tool one
> > could use..
> 
> I'm experiencing the same issue on mackerel. I don't know at which kernel 
> version the problems started in my case though.
> 
> Bisecting this would take quite a long time given the random nature of the 
> problem. If there's no other option we'll of course need to go that way, but 
> it certainly made sense to raise the matter on the list before investigating 
> it in case someone was already working on a fix (or, better, had already 
> written a fix :-)).

Well, why would they work on it if they didn't know that the issue was there?

Whatever.

Please try to add an extra pm_runtime_get() to the serial console initialization
to prevent it from being suspended and see if the problem is still reproducible
then.

Thanks,
Rafael