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Date: Sun, 6 Mar 2011 13:06:36 +0100
Message-ID: <AANLkTi=KcmqmghVxhwGvv79heRU3C+TC-v2VnWSWt7bU@mail.gmail.com>
Subject: Re: [PATCH] ARM: twd: Adjust localtimer frequency with cpufreqnotifiers
From: Linus Walleij <linus.walleij@linaro.org>
To: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Colin Cross <ccross@android.com>, Rob Herring <robherring2@gmail.com>,
        Russell King <linux@arm.linux.org.uk>,
        Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>,
        Harald Gustafsson <harald.gustafsson@ericsson.com>,
        Linus Walleij <linus.ml.walleij@gmail.com>,
        linux-kernel@vger.kernel.org,
        Rickard ANDERSSON <rickard.andersson@stericsson.com>,
        Varun Swara <Varun.Swara@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        martin persson <martin.persson@stericsson.com>,
        linux-arm-kernel@lists.infradead.org
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On Sat, Mar 5, 2011 at 9:19 AM, Santosh Shilimkar
<santosh.shilimkar@ti.com> wrote:

> While doing this patch for OMAP I also found that
> CPUFREQ notifiers does delays scaling timer frequency
> and there is a tick deviation(3-4 ms) around 1st tick and
> last tick around twd rescaling.

Is this caused by ticks that have been programmed
already (based on the previous frequency) when the scaling
takes effect? (That's most likely I think.)

The latter could be fixed by simply calling
schedule() for each CPU connected in the same core as
the TWD at the end of twd_update_cpu_frequency(),
couldn't it?

Colin what do you say?

> Another issue was not able to select higher fixed twd rate
> and found fix for the same.

Can you send out the patch?

Yours,
Linus Walleij
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