[PATCH 1/2] drivers: amba: properly handle devices with power domains

Russell King - ARM Linux linux at arm.linux.org.uk
Thu Nov 26 02:59:45 PST 2015


On Thu, Nov 26, 2015 at 11:24:50AM +0100, Ulf Hansson wrote:
> On 26 November 2015 at 09:39, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
> > Hello,
> >
> > On 2015-11-25 19:09, Russell King - ARM Linux wrote:
> >>
> >> On Wed, Nov 25, 2015 at 02:56:10PM +0100, Ulf Hansson wrote:
> >>>
> >>> On 25 November 2015 at 14:34, Marek Szyprowski <m.szyprowski at samsung.com>
> >>> wrote:
> >>>>
> >>>> Is ignoring dev_pm_domain_attach() return value a solution for you?
> >>>
> >>> That's probably better than nothing, but I wonder if it in practice
> >>> will have any effect?
> >>
> >> If the PM domain is down, then trying to tread the ID is likely to oops
> >> the kernel.
> >
> >
> > In my case kernel simply hangs (no single message, even when earlyprintk is
> > enabled)
> > instead of oopsing, that's why I've submitted this patch.
> >
> 
> Okay.
> 
> I suggest we go ahead and try that approach (ignoring the return
> value). It's "quick fix", but the easiest way forward to solve the
> problem.
> 
> My only concern is if such change impacts the boot time. We should do
> some tests to see if the change is negligible, if not we should
> probably think of something else (like keeping the PM domain powered
> until late_init).
> 
> Russell, what do you think?

I thought someone had a patch to read the ID during the match callback?

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