[Intel-gfx] reducing GM965 power usage when using inteldrmfb

[Jesse Barnes]

On Mon, 11 Jan 2010 23:50:12 +0330
Ali Gholami Rudi <aligrudi at gmail.com> wrote:

> Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> > > I have a mobile intel GM965 chip.  Is it possible to activate
> > > FBC or reduce the clock frequency without using xorg (when using
> > > only inteldrmfb)?  As far as I can tell, the xorg driver performs
> > > at least a few ioctl()s to activate FBC.
> > 
> > FBC requires a tiled buffer, which takes up a lot more memory.  It
> > should be possible to modify the fb driver's allocation to use one
> > though, which should automatically enable FBC.
> 
> What about clock frequency?  Can it be changed in inteldrmfb and
> if so, how effective is it in reducing power consumption?

The render clock frequency can't be reliably changed except in Ironlake
based chips (i.e. the new Core i7 series stuff).  The display refresh
rate can be reduced though, that should happen automatically even with
the fb driver loaded.

-- 
Jesse Barnes, Intel Open Source Technology Center