[Intel-gfx] [RFC] Unified DRM GPU frequency knobs

[Ben Widawsky]

On the Intel driver we've developed and reviewed some patches which
enable GPU frequency settings in sysfs. Similar interfaces have existed
for some time in our debugfs, but now we're getting interest from users
like PowerTOP and have decided to formalize it. Most likely other DRM
drivers have similar features; and perhaps similar proposals have gone
out in the past.

Boiling down what we've exposed in our patches:
read current GPU frequency
read/write min frequency
read/write max frequency
read HW support lowest frequency (we call this RPn)
read HW supported highest frequency (we call this RP0)
read HW recommended low frequnecy (we call this RP1)

If no interest is perceived we will move forward with these as Intel
only sysfs interfaces.

The Intel specific patches which are ready to go are here:
http://lists.freedesktop.org/archives/intel-gfx/2012-September/020342.html

Thanks.

-- 
Ben Widawsky, Intel Open Source Technology Center