[ltp] Direct Rendering's affect on battery life?

Guarded Identity linux-thinkpad@linux-thinkpad.org
Wed, 5 Apr 2006 10:12:56 -0500

Hi everyone,

I finally found a background that works well with my pseudo-transparent 
terminal emulator (it's really difficult to find one that uniformly contrasts 
well with cyan, green, blue, magenta, and red!).  Everything was working 
really nicely, so I thought I'd look into what was possible to make it even 
nicer... so I played around with installing fglrx, but before that just 
turning on DRM/DRI (which I really hadn't been using previously) to see if I 
could get anything out of XComposite, XRender, and XDamage.  I didn't get 
that far with fglrx, but I /did/ notice that DRI finally worked on the Radeon 
Mobility 9600 that's in my T42 (DRI wasn't supported for the 9600 the last 
time I played around with it).

I assume DRI is nice for mplayer or something... actually, I was getting by 
before fine without it.

One thing, though, that I think I noticed, was that my power was draining 
faster... by about 1.0 to 1.5 Watts (so not exactly an insignificant amount).  
However, I'm not so certain of this power loss; power dissipation isn't 
exactly constant, and there's a lot of settling and averaging to account for.  
I didn't exactly run a statisical experiment... just eyeballed it.

I guess I'm wondering if anyone in this forum:

    1) agrees that DRM/DRI does indeed cause a power loss, and if so
    2) knows a way to set up X to curtail the loss.

Feel free to throw in any other comments you might have too; I'm not trying to 
make this too targeted a question.

- Sukant