macfanctld does not use SMART sensors

[Daniel Weinstein]

Mac fan sensorsdo not work with anythin other than Apple OEM drives., So the only available temperature data dor replacment drives is the SMART sensors within the drive.

Even with macfancld installed the fan opperates at full speed all the time, because iti is not reading the SMART sensors

[Mikael Strom (mikael-sesamiq)]

More information needed. What Mac are you using?
Please provide a log from macfanctld.

[Daniel Weinstein (ihatewindowsxp)]

This is a feature request, not a report of an existing feature failing.

Any mac, that had the hard drive replaced with standard SATA drive, will experience this problem.

I can't provide logs because, I'm reporting a problem from the ubuntu forums.
http://ubuntuforums.org/showthread.php?p=12160768#post12160768

there are a couple of utilities, that adresss this problem under mac OS X.
HDD Fan Control - http://www.hddfancontrol.com

 UltraFan - http://forums.macrumors.com/showthread.php?t=1214206

There is a linux utility in the repositories that reports the SMART temperatures:

https://launchpad.net/ubuntu/+source/hddtemp

[deutrino (deutrino)]

Is there a reason that you can't use the average system temperature in macfanctld to control the fan speed?

[Mikael Strom (mikael-sesamiq)]

My memory is fading, but I think the reason is to slow reaction on
temp spikes (you'll be surprised how fast the temp on the GPU spikes
under max load). Average moves to slow and might create overheating.
Best regards,

Mikael Ström
SesamiQ Phil INC.
3/F Reliance House, No. 205 EDSA cor. Rochester Street,
Greenhills, Mandaluyong City 1550, Metro-Manila
Philippines
Cell: [phone]
www.sesamiq.com

On Fri, Apr 17, 2015 at 2:50 PM, gmorehou <email address hidden> wrote:
> Is there a reason that you can't use the average system temperature in
> macfanctld to control the fan speed?
>
> --
> You received this bug notification because you are subscribed to
> macfanctld.
> https://bugs.launchpad.net/bugs/1019468
>
> Title:
> macfanctld does not use SMART sensors
>
> Status in macfanctld:
> New
>
> Bug description:
> Mac fan sensorsdo not work with anythin other than Apple OEM drives.,
> So the only available temperature data dor replacment drives is the
> SMART sensors within the drive.
>
> Even with macfancld installed the fan opperates at full speed all the
> time, because iti is not reading the SMART sensors
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/macfanctld/+bug/1019468/+subscriptions
>

[deutrino (deutrino)]

I've noticed rapid temperature spikes on a Macbook CPU while monitoring macfanctld log output. I was using the average speed (somebody I think wrote that feature in after your code, maybe?) and it definitely was more reactive than the fan had been on OS X, but I'd filtered all the unknown and pointless sensors out.

So users are able, with the out of the box version in Ubuntu, to let the average temperature drive fan speed.

CPU can spike pretty fast though, changing 10-15C in as many seconds at times.

[Naël (nathanael-naeri)]

Daniel:
> Any mac, that had the hard drive replaced with standard SATA drive,
> will experience this problem.

Only iMac models released after 10/2009 and discontinued in 10/2012 (21.5"/27" aluminium unibody models with an ODD).

Daniel's request, assuming it's still pending after all these years, was for macfanctld to be able to use the S.M.A.R.T.-reported drive temperature to drive the fans.

That only concerns the users of the iMac models mentioned above who have replaced their computer's original hard-disk drive. This series of iMacs is the last one to have three fans, for the CPU, HDD, and ODD. The HDD fan is used by Mac OS X for cooling the HDD, whose temperature is reported to the SMC by an HDD temperature sensor.

Prior to 10/2009 (iMac 17"/20"/24" 01/2006-10/2009), this sensor was affixed to the outside of the drive and could be moved to the new drive. After 10/2009 and until 10/2012 (iMac 21.5"/27" 10/2009-10/2012), it is located inside the drive and a cable must be connected to certain jumper pins for the SMC to read its value. The pins to connect to are manufacturer-dependent and not publicly documented, which makes it impossible to replace the original HDD with an HDD from another manufacturer.

If I understand correctly, when the sensor cable is not connected to the right pins, it does not report a valid temperature to the SMC, whose safety features kick in (whatever the OS) and make the HDD fan spin at maximal velocity, or perhaps all the fans, I'm not sure. This behavior is reported on many blogs and forums (for instance in the ubuntuforums thread mentioned by Daniel in comment 2).

Utilities have been developed for Mac OS X which set the HDD fan speed according to the S.M.A.R.T.-reported temperature instead of the SMC-reported one (Daniel mentioned two of them in comment 2). This works around the invalid drive temperature for users who have replaced their 10/2009-10/2012 iMac HDD with one from another manufacturer, or haven't connected the sensor cable to the right pins. Daniel asked for such a feature to be built into macfanctld.

For this to happen macfanctld would first need to be able to control more than two fans and set different fans to different speeds, so that it can drive the HDD fan independently from the CPU fan (as far as I know hard-disk drives typically run at 25-45 C, while processing units run at 55-75 C). This is a useless feature for Apple laptops and post-11/2012 iMacs, which only have CPU/GPU fans, but it could be a nice feature for pre-10/2012 iMacs, where the three fans effectively cool three different pieces of hardware which are distant enough to be at different temperatures.

It is worth noting that there are other possible causes for the HDD/iMac fans to run at full speed after replacing the drive, one of them being damage to the LCD temperature sensor cable when reassembling the iMac. The following links mention various possible causes:

http://www.hddfancontrol.com/imac-hard-drive-replacement-fan-noise-issue
https://discussions.apple.com/thread/3860372
https://discussions.apple.com/thread/3749402
http://blog.macsales.com/19617-diagnosing-2009-2010-imac-fan-speed-issues-after-upgrading-the-main-har...

[Naël (nathanael-naeri)]

Gordon: about having the fans driven by the average temperature: this mode was implemented by Mikael in the very first versions of macfanctld (see http://ubuntuforums.org/archive/index.php/t-1467062.html). I'm pretty sure it's never used since CPU/GPU proximity temperatures (sensors TC0P and TG0P) are always higher than the average temperature.

About CPU/GPU die temperatures spiking very fast (sensors TC0D and TG0D): yes, and this is why Mikael decided on using the proximity temperature sensors instead (see same forum thread). Using sensors that are not directly on the die allow for the temperature spikes to be naturally filtered out.