[PATCH 9/9] [ARM] tegra: Add cpufreq support
ccross at google.com
Fri Jul 30 16:33:08 EDT 2010
On Fri, Jul 30, 2010 at 1:20 PM, Mark Brown
<broonie at opensource.wolfsonmicro.com> wrote:
> On Fri, Jul 30, 2010 at 12:56:33PM -0700, Colin Cross wrote:
>> On Fri, Jul 30, 2010 at 6:11 AM, Dominik Brodowski
>> >> + ? ? ret = clk_set_rate_cansleep(cpu_clk, freqs.new * 1000);
>> > "can sleep"? For how long?
>> Adjusting the CPU clock may require changing the voltage through the
>> regulator api, which locks a mutex, and eventually through I2C, which
>> sleeps on I2C completion.
> ...although in some systems the I2C cost will be replaced with updating
> a GPIO which is very much cheaper.
Yes, but even on a GPIO regulator, the regulator api will lock a mutex
and possibly schedule.
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