Thread (42 messages) 42 messages, 7 authors, 2014-06-07

[RFC PATCH 0/5] Frequency resolution in CCF vs. cpufreq

From: viresh.kumar@linaro.org (Viresh Kumar)
Date: 2014-05-15 06:12:13
Also in: linux-pm, lkml

On 15 May 2014 04:00, Soren Brinkmann [off-list ref] wrote:
I have one or two problems with cpufreq and the CCF, which are caused by
rounding/different frequency resolutions.

cpufreq works with kHz, while the CCF uses Hz. On Zynq our default frequency is
666666666 Hz which the CCF, due to rounding, reports as 666666660. And for
cpufreq, which simply divides values it obtains through clk_round_rate() by
1000, 666666.
Since passing 666666 to clk_round_rate() does not result in 666666660
(clk_round_rate() always rounds down!), we chose to put 666667 in the OPP. This
causes issue 1: cpufreq stats are broken.
I know it might a big exercise, but wouldn't it be worth to make cpufreq start
using frequencies in Hz ?
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