[ltp] Everlasting Fan

Alex Deucher linux-thinkpad@linux-thinkpad.org
Tue, 14 Jun 2005 09:43:43 -0400


On 6/14/05, Thomas Hartwig <t.hartwig.news@itth.com> wrote:
> Hello,
>=20
> unfortunately ATI still makes no advantages on linux, so I'm wondering
> if anybody can give some deeper help on debugging the xorg provided
> radeon driver.
>=20
> My experiences are that the temperature of the GPU is the most biggest
> problem related to the fan for my T40p. Typical values are:
> CPU: 44=B0C GPU: 52=B0C HDD: 32=B0C PCI: 42=B0C. I have decided to turn o=
ff the
> fan below 50=B0C, but independent of the output of X or console the
> temperature is always at about 50=B0C or higher for the GPU.
>=20
> The radeon driver has the nice option "DynamicClocks" which might alter
> the power of the display. I'm wondering now if you can fine tune this in
> a better way and see what is going on. I have already taken a small look
> into the source but I'm afraid without much time I'm not able to
> disassemble this ;-)

The dynamic shifting of the clocks is handled by the hardware, itself.
 I'm not sure exactly what its algorithm is.  Pretty much all the code
does is enable the right combination of enable dynamic clocking bits
in the various clocks.  BTW, the code has some bugs in it that I need
to fix at some point.  Also just to clarify, this is not powerplay.=20
Powerplay is more involved and ati hasn't released the information
needed to do it.

> What would be helpful is: at what clock the GPU is always running and
> what the strategy for the regulator is.
> Is there anybody out there who might be interested in looking at or has
> already done?

A while back someone posted a utility (maybe on xorg, or dri-devel)
that allowed you to statically adjust the GPU clock rate.

>=20
> Perhaps I will contact the author of the code as well.
>=20

Ati wrote the code, I just cleaned it up a bit and committed it to cvs.

Alex

> Best regards
> Thomas
>