Manually set Chromebook Pixel (2015) fans to maximum speed?

[Eli Grey]

Is there any way in crosh or in my Ubuntu crouton chroot to manually set the fan to maximum speed?

Whenever I start intensive gaming in crouton with my 2015 Chromebook Pixel LS, the fans never seem to clock up past "very slow" and I suffer from thermal throttling. Because of this, I get very bad gaming performance compared to what I get with a very similar laptop with the exact same i7 5500U CPU.

I have normalized the following tests for resolution (1280x720), video settings (everything at low, texture detail at medium), map (safehouse). The XPS is running Ubuntu natively and the Pixel is running Ubuntu with the Chrome OS kernel (through crouton).

On my XPS 13 (2015) with an i7 5500U, I get a constant 50-60fps while playing CS:GO at 720p. The single fan clocks up to dissipate the extra heat from gaming.

On my Chromebook Pixel LS (2015) with an i7 5500U, I get a constant 5-10fps while playing CS:GO at 720p. The fan noise is equivalent to what I get with moderate web browsing. Neither of the two fans in the Pixel automatically clock up any further.

[David Hendricks]

The fan is usually controlled by the embedded controller (EC). There is a utility called "ectool" that you can use to tweak many things, including fan duty cycle.

Give this a try at the shell: "sudo ectool fanduty 100"

That should set the fan's duty cycle to 100%, and I believe it disables the automatic fan control algorithm as well. There are a few other commands you can play with (pwmgetfamrpm, pwmsetfanrpm) to find a good balance of speed/noise.

--
--
Chromium OS Developers mailing list: chromiu...@chromium.org
View archives, change email options, or unsubscribe:
http://groups.google.com/a/chromium.org/group/chromium-os-dev?hl=en

To unsubscribe from this group and stop receiving emails from it, send an email to chromium-os-d...@chromium.org.

--

David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.

[Eli Grey]

Thank you Shawn M and David. "sudo ectool fanduty 100" fixed my problem! Now the next problem is figuring out why the fans aren't automatically clocking up fast enough when necessary. Is there a hardcoded limit to the automatic fan control? If so, why is the limit not 100%?

[Shawn N]

I believe the fan control on Samus is largely defined by the fans[] table here:

https://chromium.googlesource.com/chromiumos/platform/ec/+/master/board/samus/board.c

Regarding why the fan is never set to 100% duty cycle, I can't speak to this particular design, but in my experience there are non-linear relationships between duty cycle / fan RPM, and between fan RPM / noise. So, for example, if 80% duty cycle spins the fan at 7000 RPM and is nearly silent, but 100% duty cycle spins the fan at 7200 RPM and annoys the neighbors, then the system designer may decide that 80% max duty cycle is a good trade-off.

[Chang Liu]

Hi, 

I have a chromebook pixel 2013, and i happen to use ectool to solve fan speed problems. the command "sudo ectool fanduty 40" seems only works for 5 seconds, and then it goes back to normal. it spins faster when the temperature goes up. is there any solution to this ? 

Thanks.