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From: Viresh Kumar <viresh.kumar@linaro.org>
To: vichy <vichy.kuo@gmail.com>
Cc: "cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: about system time incorrect after changing cpu frequency
Date: Tue, 1 Sep 2015 11:32:36 +0530	[thread overview]
Message-ID: <20150901060236.GB1456@linux> (raw)
In-Reply-To: <CAOVJa8HNQ-s=yDfADCcoL+r22ALpHFtTjWZ=oxTkBUriYbCk+Q@mail.gmail.com>

On 01-09-15, 13:36, vichy wrote:
> >> I try to call below 2 functions to change the frequency of clocksource
> >> and clockevent, but the above b) sleep time is still incorrect when
> >> cpu runs in 500Mhz.
> >>     clockevents_update_freq(this_cpu_ptr(gt_evt), gt_clk_rate);
> >>     __clocksource_updatefreq_hz(&gt_clocksource, gt_clk_rate);

How and when were you calling them? What kernel version is it ?

> Clock Event Device: arm_global_timer

This driver doesn't have support to update clkevt device's freq. You
may need to modify that based on how arch/arm/kernel/smp_twd.c is
updated. look for: clockevents_update_freq().

-- 
viresh

WARNING: multiple messages have this Message-ID (diff)
From: viresh.kumar@linaro.org (Viresh Kumar)
To: linux-arm-kernel@lists.infradead.org
Subject: about system time incorrect after changing cpu frequency
Date: Tue, 1 Sep 2015 11:32:36 +0530	[thread overview]
Message-ID: <20150901060236.GB1456@linux> (raw)
In-Reply-To: <CAOVJa8HNQ-s=yDfADCcoL+r22ALpHFtTjWZ=oxTkBUriYbCk+Q@mail.gmail.com>

On 01-09-15, 13:36, vichy wrote:
> >> I try to call below 2 functions to change the frequency of clocksource
> >> and clockevent, but the above b) sleep time is still incorrect when
> >> cpu runs in 500Mhz.
> >>     clockevents_update_freq(this_cpu_ptr(gt_evt), gt_clk_rate);
> >>     __clocksource_updatefreq_hz(&gt_clocksource, gt_clk_rate);

How and when were you calling them? What kernel version is it ?

> Clock Event Device: arm_global_timer

This driver doesn't have support to update clkevt device's freq. You
may need to modify that based on how arch/arm/kernel/smp_twd.c is
updated. look for: clockevents_update_freq().

-- 
viresh

  reply	other threads:[~2015-09-01  6:02 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-31 14:03 about system time incorrect after changing cpu frequency vichy
2015-08-31 14:03 ` vichy
2015-09-01  3:57 ` Viresh Kumar
2015-09-01  3:57   ` Viresh Kumar
2015-09-01  5:36   ` vichy
2015-09-01  5:36     ` vichy
2015-09-01  6:02     ` Viresh Kumar [this message]
2015-09-01  6:02       ` Viresh Kumar
2015-09-01  6:39       ` Jisheng Zhang
2015-09-01  6:39         ` Jisheng Zhang
2015-09-01  7:37         ` vichy
2015-09-01  7:37           ` vichy
2015-09-01  7:21       ` vichy
2015-09-01  7:21         ` vichy
2015-09-01  7:42         ` Viresh Kumar
2015-09-01  7:42           ` Viresh Kumar

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