linux-kernel - Re: [PATCH] cpufreq: arm_big_little: fix frequency check when bL switcher is active

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Message-ID: <5624AD5F.7020807@arm.com>
Date:	Mon, 19 Oct 2015 09:44:15 +0100
From:	Sudeep Holla <sudeep.holla@....com>
To:	"Jon Medhurst (Tixy)" <tixy@...aro.org>
Cc:	Sudeep Holla <sudeep.holla@....com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: arm_big_little: fix frequency check when bL
 switcher is active



On 19/10/15 09:33, Jon Medhurst (Tixy) wrote:
> On Wed, 2015-10-14 at 09:48 +0100, Sudeep Holla wrote:
>>

[...]

>>
>> OK, I understand what you mean now. I don't have a strong opinion, but
>> here is the reason why I prefer the approach I said earlier:
>> clk_set_rate doesn't return error if the h/w or f/w return error which
>> is usually the last step. So calling clk_get_rate when clk_set_rate
>> return error quite early makes no sense to me.
>
> It doesn't to me either, but my suggested code doesn't do that, it only
> calls clk_get_rate if the is _no_ error from clk_set_rate, the pseudo
> code again...
>
> ret = clk_set_rate()
> if(!ret)                         /* if no error from clk_set_rate   */
>      if(clk_get_rate()!=correct)  /* but some additional checks fail */
>          ret = -EIO;              /* then indicate an error anyway   */
>
> !ret is ret==0 is 'no error' as the comment says. So the clock framework
> thinks the rate was set OK and we then use clk_get_rate to see if those
> unreported h/w or f/w errors mean that it actually wasn't set OK.
>

Ah sorry, my mistake. May be I got carried away by that extra if(!ret).
I am fine with the patch.

Acked-by: Sudeep Holla <sudeep.holla@....com>

-- 
Regards,
Sudeep
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