ibm-acpi Linux driver development

Alessandro Crismani | 22 Apr 2011 10:19

Thinkpad T420s thermal support

Hi everybody,

I've just bought a thinkpad T420s and I love it. The only issue I have at the 
moment is with the fan control and the thermal management. In particular I 
have no /proc/acpi/imb/thermal and no /proc/acpi/ibm/ecdump (even with 
experimental=1). What I see is only:

[root <at> alessandro-thinky alessandro]# ls /proc/acpi/ibm/
beep  bluetooth  cmos  driver  fan  hotkey  led  light  video  volume

Other info from dmesg is:
[root <at> alessandro-thinky alessandro]# dmesg | grep think
thinkpad_acpi: ThinkPad BIOS 8CET28WW (1.05 ), EC unknown
thinkpad_acpi: Lenovo ThinkPad T420s, model 417032U
thinkpad_acpi: detected a 8-level brightness capable ThinkPad
thinkpad_acpi: radio switch found; radios are enabled
thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio is unblocked
Registered led device: tpacpi::thinklight
Registered led device: tpacpi::thinkvantage
thinkpad_acpi: Standard ACPI backlight interface available, not loading native 
one.
thinkpad_acpi: Console audio control enabled, mode: monitor (read only)
input: ThinkPad Extra Buttons as /devices/platform/thinkpad_acpi/input/input11

Finally, sensors reports:
[root <at> alessandro-thinky alessandro]# sensors
thinkpad-isa-0000
Adapter: ISA adapter
fan1:        3092 RPM

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Henrique de Moraes Holschuh | 22 Apr 2011 13:02

Re: Thinkpad T420s thermal support

On Fri, 22 Apr 2011, Alessandro Crismani wrote:
> I've just bought a thinkpad T420s and I love it. The only issue I have at the 
> moment is with the fan control and the thermal management. In particular I 
> have no /proc/acpi/imb/thermal and no /proc/acpi/ibm/ecdump (even with 
> experimental=1). What I see is only:

Yeah, Lenovo is disabling these stuff as of lately, but it could simply be
lack of support for the T420 in the driver.   I'd need a boot with the
"debug=0xffff" parameter of thinkpad-acpi to tell you more.

> I am also seeing rather high fan speeds. If the laptop is left idle the fan 

You could open a bug against the ACPI component in bugzilla.kernel.org, as
this is a general problem (and not thinkpad-acpi-related) with the latest
thinkpads.  Might be related to the GPU as well.  What GPU do you have in
your thinkpad?

It could also be on purpose, as Linux has no clue about some of the stuff
inside the newer thinkpads with nvidia optimus, and doesn't do everything
Lenovo's extra windows drivers do, Lenovo might have arranged to keep the
fan always on.

E.g. if no ATM (advanced temperature management) driver registers with the
thinkpad-ec, use a more fan-happy profile.  Since only Lenovo knows about
the ATM interface (I only know it exists because they told me it exists, and
apparently it has much more to do with the OS than anything else than
telling the thinkpad that the OS is going to go nutters to not output much
power), well...

> spins continuously (at low speed, but it still spins, even if the laptop is

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Alessandro Crismani | 23 Apr 2011 13:00

Re: Thinkpad T420s thermal support

Hi, thanks for your reply!

In data venerdì 22 aprile 2011 08:02:28, hai scritto:
> On Fri, 22 Apr 2011, Alessandro Crismani wrote:
> > I've just bought a thinkpad T420s and I love it. The only issue I have
> > at the  moment is with the fan control and the thermal management. In
> > particular I have no /proc/acpi/imb/thermal and no
> > /proc/acpi/ibm/ecdump (even with
> 
> > experimental=1). What I see is only:
> Yeah, Lenovo is disabling these stuff as of lately, but it could simply be
> lack of support for the T420 in the driver.   I'd need a boot with the
> "debug=0xffff" parameter of thinkpad-acpi to tell you more.

I hope you need a dmesg log, you'll find it attached to this mail. If you need 
something else let me know!

> > I am also seeing rather high fan speeds. If the laptop is left idle the
> > fan 
> 
> You could open a bug against the ACPI component in bugzilla.kernel.org, as
> this is a general problem (and not thinkpad-acpi-related) with the latest
> thinkpads.

Will I have better results with the LTS kernel? I might try that, but I am not 
sure how many of the drivers included in latest kernel have been backported. I 
am relying on thr rtl8192ce driver for wireless (included in 2.6.28) that will 
probably be misisng on LTS and I am not sure whether Sandy Bridge GPUs are 
supported.

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