Re: [PATCH V2] cpufreq: Make sure CPU is running on a freq from freq-table

From: Rafael J. Wysocki
Date: Tue Nov 26 2013 - 15:08:40 EST


On Tuesday, November 26, 2013 07:31:50 AM Viresh Kumar wrote:
> On 26 November 2013 02:43, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > On Monday, November 25, 2013 09:43:59 AM Dirk Brandewie wrote:
> >> This is a platform specific bug fix AFAICT and belongs in a platform
> >> specific piece of code
>
> In case we end up doing that, we will do lots of code redundancy in
> cpufreq drivers. And as Rafael said, some platforms might never
> know they have booted with an out of table frequency and so taking
> care of this at a single place is better, where we are sure that it
> will get fixed.
>
> >> The core should not be working around bootloader bugs IMHO. Silently
> >> fixing it is evil IMHO at a minimum the core should complain LOUDLY
> >> about this happening otherwise the bootloaders will have no incentive to
> >> get their act together.
>
> That looks correct..
>
> > Yes, we can add a WARN_ON() there. Still, though, the core's responsibility
> > is to ensure that (a) either we can continue safely or (b) we can't, in which
> > case it should just fail the initialization. Whether or not it should panic()
> > I'm not sure.
>
> But is this that big crime, that we do a WARN on it? CPU was running on
> a workable frequency, it wasn't mentioned in the table, that's it.
>
> Probably just throw an print message that CPU found to be running on
> out of table frequency, and that got fixed..

I was talking about the case when your

__cpufreq_driver_target(policy, policy->cur - 1, CPUFREQ_RELATION_L);

fails. The other case is not really interesting.

Thanks!

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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