linux-kernel - Re: [PATCH V2 5/7] cpufreq: imx6q: don't initialize opp table

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Date:	Wed, 21 May 2014 22:16:24 +0800
From:	Shawn Guo <shawn.guo@...aro.org>
To:	Sudeep Holla <sudeep.holla@....com>
CC:	Viresh Kumar <viresh.kumar@...aro.org>,
	"rjw@...ysocki.net" <rjw@...ysocki.net>,
	"linaro-kernel@...ts.linaro.org" <linaro-kernel@...ts.linaro.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Arvind Chauhan <Arvind.Chauhan@....com>,
	"inderpal.s@...sung.com" <inderpal.s@...sung.com>,
	"nm@...com" <nm@...com>,
	"chander.kashyap@...aro.org" <chander.kashyap@...aro.org>,
	"pavel@....cz" <pavel@....cz>,
	"len.brown@...el.com" <len.brown@...el.com>
Subject: Re: [PATCH V2 5/7] cpufreq: imx6q: don't initialize opp table

On Wed, May 21, 2014 at 03:07:36PM +0100, Sudeep Holla wrote:
> >@@ -376,7 +356,7 @@ static void __init imx6q_init_late(void)
> >  		imx6q_cpuidle_init();
> >
> >  	if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ)) {
> >-		imx6q_opp_init();
> >+		imx6q_opp_check_speed_grading();
> 
> [Query] Not exactly related to this patch, but asking it here to get clarified.
> 
> This OPP limiting is done as part of late initcall and if the cpufreq driver is
> built in the kernel, there will be a small window where the OPPs not supported
> are still enabled ? Will that not be an issue if say performance governor is
> selected by default.

Even if cpufreq driver is built in the kernel, it won't be probed until
platform_device_register(&imx6q_cpufreq_pdev) is called.  And we make
this call only after the OPP limiting.

Shawn
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