[ltp] T60p idle GPU temperature?

[Alex Deucher]

On Thu, Jul 12, 2012 at 12:16 AM, Henrique de Moraes Holschuh
<hmh@hmh.eng.br> wrote:
> On Mon, 09 Jul 2012, Alex Deucher wrote:
>> On Sat, Jul 7, 2012 at 11:38 AM, Henrique de Moraes Holschuh
>> <hmh@hmh.eng.br> wrote:
>> > 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.
>>
>> The UMS dynamic clocks option just used a lower clock speed when the
>> displays were off.  The KMS code does the same thing with both dynpm
>> and profiles.  KMS uses the GPU a lot more than UMS did (uses the GPU
>> to accelerate GPU buffer moves, dynamically uses GART, etc.).
>
> Hmm, that means something in X.org is keeping KMS busier than it should.

Actually you have to switch to a profile other than default in order
to clock down when the displays are off.  Try auto.

>
>> > 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 :-(
>>
>> It's changing the number of PCIE lanes that causes this.  You can
>> disable that code (rv370_set_pcie_lanes()).  The host bridge doesn't
>> seem to like having the lanes switched on it when it's running and
>> generates the NMI.
>
> Nah, it already draws too much power as it is, can't have extra PCIe lanes
> enabled.  Did you ask any of the Intel regulars for some help with the
> 915PM?  Or does it happen only on thinkpads, and therefore the thinkpad
> firmware is to blame?

I don't know if it's specific to thinkpads or not (or even certain
chipsets).  I've never had the time to debug it in detail.  IIRC, the
UMS radeon driver has identical pcie lane code.  Did you have similar
issues with UMS and pcie lane switches?

Alex

>
> --
>   "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