[Intel-gfx] Framebuffer compression on GM45 disabled with KMS

[Tino Keitel]

On Mon, May 03, 2010 at 00:35:34 +0100, Pedro Ribeiro wrote:

[...]

> Hi Tino,
> 
> this gains have been mostly with the computer sitting idle and me not
> touching it. The biggest gain (over 1w) is when I let the monitor go
> off into powersaving mode. There is a clear difference here. But maybe
> its just for my chipset...

I only test with the LCD switched on, but set to lowest brightness.

In the previous test, I had wrong kernel options. The i915. prefix was
missing.  Now I tested again and got down to 7.0W:

Wakeups-from-idle per second :  8.0     interval: 30.0s
Power usage (ACPI estimate): 7.0W (3.9 hours) (long term: 7.8W,/3.4h)

I also changed the background image to solid color for better FBC. What
I noticed during my tests is that I only get such low numbers after a
resume from suspend to RAM.  Power consumption is ~0.5W higher after a
resume from suspend to disk using TuxOnIce.  IMHO this should not
happen.  So, overall I get lower values with the current configuration,
but I don't know what change gives the power saving, and the suspend
issue makes it hard to compare.  It could also be a combination of some
of the configuration changes.

Regards,
Tino