linux-kernel - Re: [PATCH V3 3/9] cpufreq: Cap the default transition delay value to 10 ms

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Date:   Wed, 16 Aug 2017 12:42:45 +0300
From:   Leonard Crestez <leonard.crestez@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        Rafael Wysocki <rjw@...ysocki.net>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>
CC:     <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        <linux@...inikbrodowski.net>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 3/9] cpufreq: Cap the default transition delay value
 to 10 ms

On Wed, 2017-08-16 at 12:04 +0530, Viresh Kumar wrote:
> On 28-07-17, 10:58, Viresh Kumar wrote:
> > 
> > At this point I really feel that this is a hardware specific problem
> > and it was working by chance until now. And I am not sure if we
> > shouldn't be stopping this patch from getting merged just because of
> > that.
> > 
> > At least you can teach your distribution to go increase the sampling
> > rate from userspace to make it all work.
> Its been 3 weeks since my last email on this thread and no reply yet
> from any of the IMX maintainers. Can someone please help here ?
> 
> @Shawn: Can you help debugging a bit here, to see what's get screwed
> up due to this commit ? Its just that your platform isn't able to
> change freq at 10 ms rate.
> 
> @Rafael: I am not sure, but should we be stopping this patch because
> some hardware isn't able to change freq at 10ms interval and is just
> faking the transition delay to start with ?
> 
> Maybe we get this merged again and the IMX guys can figure out what's
> wrong on their platform and how to fix it ?

I reported the initial issue but did not have the time to do a more
thorough investigation, this is more complicated than it seems. I said
this before but maybe it got lost:

I don't think the odd behavior I noticed justifies keeping the patch
from merging.

--
Regards,
Leonrd