Fan or Thermal settings for Dell laptops and SMM codes

Pali Rohár pali.rohar at gmail.com
Fri May 29 02:42:27 CDT 2015


Here is link for "Dell Command | Power Manager" for Windows 7 and 8:
http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=VJMDY

But it only for Latitude xx40 and xx50 series, not for xx30.
So this is probably reason why you did not found it...

Rob already tested it (November 2014) and wrote that utility really do
something with thermal/fan management...

On Friday 29 May 2015 13:01:40 Srinivas_G_Gowda at Dell.com wrote:
> 
> Pali,
> The windows utility that you referred to "Dell Command | Power Manager". Did you get a chance to test it on a E6440  ?
> I have a Latitue E6430, these flags are not supported on this either.  Also I did not find "Dell Command | Power Manager" tool for windows7 !!!
> 
> 
> Thanks,
> G
> 
> On Friday 29 May 2015 12:54 PM, Pali Rohár wrote:
> > Hello,
> >
> > it looks like those tokens are not supported on Latitude E6440 :-(
> >
> > On Friday 29 May 2015 10:41:15 Srinivas_G_Gowda at Dell.com wrote:
> >> Hi,
> >> There are several tokens available that lets you to control the fan settings.  You can use "smbios-token-ctl" libsmbios utility to play with it. Just run smbios-token-ctl to list the supported flags on your laptop.
> >>
> >> 00BD,"System Fan Speed","Full Speed","Fan speed set to normal cooling.",,
> >> 00BE,"System Fan Speed","Noise Reduced","Fan speed set to slow to reduce noise.",,
> >> 02FD,"Fan Control Override",Enable,"When Enabled, the system fan runs at full speed",3.000,
> >> 02FE,"Fan Control Override",Disable,"When Disabled, the fan controller uses system environmental data to set the fan at its optimal speed",3.000,
> >> 0332,"Fan Speed",Auto,"System uses environmental data to set fan speed",3.002,
> >> 0333,"Fan Speed",High,"Fans run at maximum speed",3.002,
> >> 0334,"Fan Speed",Medium,"Fans run at medium speed",3.002,
> >> 0335,"Fan Speed",Low,"Fans run at low speed",3.002,
> >> 02FD,"Fan Control Override",Enable,"When Enabled, the system fan runs at full speed",3.000,
> >> 02FE,"Fan Control Override",Disable,"When Disabled, the fan controller uses system environmental data to set the fan at its optimal speed",3.000,
> >> 0332,"Fan Speed",Auto,"System uses environmental data to set fan speed",3.002,
> >> 0333,"Fan Speed",High,"Fans run at maximum speed",3.002,
> >> 0334,"Fan Speed",Medium,"Fans run at medium speed",3.002,
> >> 0335,"Fan Speed",Low,"Fans run at low speed",3.002,
> >>
> >>
> >> There is a Thermal feature that I am working on, not sure if directly affects the fans. But please watch out for an update from me on the mailing list by early next week.
> >>
> >>
> >> Thanks,
> >> G
> >>
> >>
> >> On Thursday 28 May 2015 09:31 PM, Carlos Alberto Lopez Perez wrote:
> >>> On 28/05/15 10:25, Pali Rohár wrote:
> >>>> Hello,
> >>>>
> >>>> do you have any other information about reading temperature or setting
> >>>> fan speed on Dell Latitude laptops? 
> >>>>
> >>>> On Tuesday 11 November 2014 18:22:05 Pali Rohár wrote:
> >>>>> Hello,
> >>>>>
> >>>>> Rob (CCed) wrote me that Dell now (28 Oct 2014) released new tool 
> >>>>> for Windows 8 operating systems which can control fan speed. Its 
> >>>>> name is "Dell Command | Power Manager" and new version 2.0.0, A00 
> >>>>> has this line in description:
> >>>>>
> >>>>> Fixes & Enhancements
> >>>>> - Added Thermal Management Feature
> >>>>>
> >>>>> Tool can be downloaded from this link:
> >>>>>
> >>>>> http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=VJMDY&fileId=3405572508&osCode=W764&productCode=latitude-e6440-laptop&languageCode=EN&categoryId=UT
> >>>>>
> >>>>> Srinivas or Michael: Are you able to find out which interface is 
> >>>>> that new version of tool using? And how can it change fan speed? 
> >>>>> Can be fan support implemented also on Linux?
> >>>>>
> >>> I'm also interested in being able to control the fan of a Latitude E6420
> >>> from Linux.
> >>>
> >>> On the Linux Kernel there is a driver, i8k, that can change the fan
> >>> speed. Unfortunately the SMM/BIOS will override the speed automatically.
> >>> So the changes on the speed of the fan only last a second.
> >>>
> >>> I created an utility that does this in user-space [1]. I also managed to
> >>> find some codes to disable the automatic SMM control of the fan. So I
> >>> can control the fan at will.
> >>>
> >>> The problem is that when i disable this SMM automatic control weird
> >>> things happen like my Fn keys stop working or the computer halts instead
> >>> of suspending.
> >>>
> >>> Can Dell please share here the SMM codes to disable the automatic
> >>> BIOS/SMM control of the fan without causing unrelated problems on the
> >>> system? Or share a way to reliable increase or decrease the speed of the
> >>> fan at will?
> >>>
> >>> Thanks
> >>> ------
> >>>
> >>> [1]
> >>> Only works if you are running Linux 64-bit (I removed the support for
> >>> 32-bits but should be possible to be added back looking at the source
> >>> code of i8k)
> >>> https://github.com/clopez/dellfan
> >>>
> >>>

-- 
Pali Rohár
pali.rohar at gmail.com



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