On 13 October 2010 16:14, Amit Kucheria <amit.kuche...@linaro.org> wrote: > On Wed, Oct 13, 2010 at 4:35 PM, Vincent Guittot > <vincent.guit...@linaro.org> wrote: >> Hi, >> >> Exporting the clock tree state is help us to monitor clocks state and >> to find the guilty clocks. But could it be also possible to have a >> write access to the clock tree ? During power consumption optimization > > That is an interesting idea. > >> step, we need to identify clock/regulator which should be disable but >> we also want to know what will be the gain. Instead of waiting for the >> new code with the right clock management, we generally want to >> directly disable it and look at the 1st result. It will be also useful >> when we are looking for the best clock tree configuration without >> developing/modifying a lot of source code. > > Do you anticipate any other interface besides making the 'rate' sysfs > file RW and controlling the clock by writing various rates to the > file? > > So, > 0 - clock off > any other positive value - round down to the nearest valid rate > > and writing to the file would lead to a call to clk.set_rate() >
my idea is to export the clock interface through the debugfs for the optimization phase. Then each machine implements and exports the supported function. >> For sure, such kind of feature is quite dangerous and must be enable >> carefully but it would help for optimizing power consumption. > > I'm not sure that all clock frameworks are even ready for this feature > today, especially if they don't handle recalculation of child clock > rates as part of set_rate(). > > /Amit > _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
