[PATCH 0/3] Add support for Tegra Activity Monitor
acourbot at nvidia.com
Fri Nov 7 01:07:24 PST 2014
On 10/29/2014 11:50 PM, Tomeu Vizoso wrote:
> these patches implement support for setting the rate of the EMC clock based on
> stats collected from the ACTMON, a piece of hw in the Tegra124 that counts
> memory accesses (among others).
> It depends on the following in-flight patches:
> * MC driver: http://thread.gmane.org/gmane.linux.ports.tegra/19623
> * EMC driver: http://thread.gmane.org/gmane.linux.ports.arm.kernel/365125
> * CPUFreq driver: http://thread.gmane.org/gmane.linux.kernel/1812962
> I have pushed a branch here for testing:
I am not too familiar with DVFS, but after going through this series it
really seems to me that this could use devfreq. In its current form this
driver mixes control and policy and lacks flexibility, preventing e.g.
to switch to a performance or power-saving profile. Could you study the
feasibility of using devfreq for this?
I also wonder if this driver could not be made more flexible generally
speaking - right now it is hardcoded that you can only control EMC
frequency with it. I can imagine that we could want to control several
clocks using the same counter information, and that e.g. a notifier
block might help with that. But let's keep that for later - whether to
use devfreq or not seems to be the most important question for now.
More information about the linux-arm-kernel