[ltp] Re: controlling Fire GL power levels on T43p

[Fionn Behrens]

On Mi, 2005-11-23 at 10:59 +0200, Nir Tzachar wrote:
> hello list.
>=20
> im new here, but have found many useful thing on the archives and the
> thinkwiki wiki in the past.=20
>=20
> I have one question which i did not manage to find an answer to;
> if i use ATI's propriety drivers for the bundled FireGL V3200, i can
> control the power level of the card. this can squeeze almost 45 to 60
> minutes of juice from my battery. However, im not very inclined to using
> the closed sourced driver.
> So, i was wondering, does anyone know of a way to control the power
> levels of the graphics card without using this driver?=20
> even a direction to get me going will be nice, as i have no idea

Unfortunately the original "powerplay" stuff contains tricks like
disabling memory bus lanes and stuff and nobody except ati know how to
do that. Speculations are that ATI doesn not open the source because
they are afraid of being sued for infringing on patented stuff like
speedstep[tm] and the like. Thank the US government for "freeing" the
world with their shoddy software patents shit.

The open r300 driver can be told to save power by enabling the
"DynamicClocks" option in xorg.conf, which turns down the clock speed of
the radeon chip when it is idle.
On my system the difference between fglrx and r300 is not as big as I
expected. I have not taken exact measures though, I just watched the
temperature readings and the difference is about 1-2=B0C max.

Additionally, there is an open tool named "rovclock", designed to
overclock radeon chips in linux. It can, however, be used to underclock
your card, too. Try to set a gpu clock rate of 95MHz and memory clock to
120MHz. (powerplay sets both to about 200 at minimum). Dont hesitate to
experiment a bit - if you go too low, you will see random pixels on the
screen first - the GPU does not crash right away.

best regards,
		Fionn