[ltp] T60p idle GPU temperature?

Henrique de Moraes Holschuh linux-thinkpad@linux-thinkpad.org
Sat, 7 Jul 2012 12:38:14 -0300

On Sat, 07 Jul 2012, Alex Deucher wrote:
> > The Linux ATI framebuffer/DRM power management is crap, at least for the
> > X300/X600/X1500/X1600 ATIs, so it really runs the GPU a lot hotter (and
> > wastes a lot more power) than what non-KMS X.org used to do, and let's not
> > even compare it to what fglrx could do...
> The radeon KMS and non-KMS pm support is mostly identical.  If you are
> experiencing differences, it's probably due to the fact that KMS
> utilizes the GPU more readily than UMS did.

Dynamic clocks worked somewhat well with non-KMS.  This is not true for KMS
IME, at least not for the R300 family.

I've numerically tested this at the time one still could run non-KMS, with
the built-in thinkpad power-meter (when in battery mode), and also by the
built-in planar temperature sensor which sits close to the GPU on a T43
(Radeon X300).

I've been running the latest 3.0 kernel, and power management didn't improve
much.  Unless one also needs up-to-date mesa for better power saving modes
to work?  I'm runing a very outdated mesa from Debian stable, after all...

Still, I recall that the difference was very noticeable on an mostly idle
GPU (static screen, no OpenGL context active, no composition manager

That said, you're probably aware that switching power profiles in the
current KMS code (well, up to kernel 3.0 KMS code to be exact) causes some
sort of PCIe transient error in several ThinkPads, that results in unhandled
NMIs (reasons a0 and b0 on a T43 2687).  This has been reported, but no
solution has been found so far.  I'm living with it, since it doesn't seem
to cause any instability to the box, but it is annoying :-(

  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh