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

Viresh Kumar viresh.kumar at linaro.org
Wed May 14 23:12:09 PDT 2014


On 15 May 2014 04:00, Soren Brinkmann <soren.brinkmann at xilinx.com> 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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