Massive power regression going 3.4->3.5

[James Bottomley]

On Mon, 2012-07-30 at 09:33 -0700, Keith Packard wrote:
> James Bottomley <James.Bottomley at HansenPartnership.com> writes:
> 
> > OK, I've run the bisect as far as I can.  It looks to be in the drm
> > tree.  Unfortunately, this tree has several merge points, some of which
> > go further back than v3.4.  Unfortunately, once the bisect steps back
> > before 3.4, we lose the changes that gave us the power savings, making
> > further debugging impossible
> 
> What machine is this on? There are a few 'disable some power savings'
> patches in that list to work around issues on various machines; knowing
> what machine you're using can isolate which ones might have had some
> effect on power usage...

Lenovo X220i

The display device is

00:02.0 VGA compatible controller: Intel Corporation
82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
(prog-if 00 [VGA controller])
        Subsystem: Giga-byte Technology Device 2562
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at e0000000 (32-bit, prefetchable) [size=128M]
        Memory at e8200000 (32-bit, non-prefetchable) [size=512K]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: <access denied>
        Kernel driver in use: i915


James