mjg59 | Fixing Asus UX21e unexpected power off

Edit: Sigh, some further testing shows that it seems better, but not fixed. If you unplug the power while the CPU is over 80 degrees C, the machine will power off. I can't find any way of avoiding this - it seems to be handled at the embedded controller or SMM level, since as far as I can tell Linux isn't surviving long enough to even be aware that the event occurred.

Original entry:

The Asus UX21e (and maybe the UX31e?) has the irritating misfeature that it reloads the CPU thermal tables when you unplug the power. One consequence of this is that it'll automatically throttle itself much more aggressively on battery (reducing performance) but the more serious one is that the new critical power off temperature may then be lower than the temperature the CPU is currently operating at, resulting in the machine turning itself off. As far as I can tell from debugging, this is completely OS-independent - it still happens even if I stub out all the ACPI code for power supply events and there are reports of the same thing occurring on Windows. The good news is that it seems to be fixed in newer firmware versions. The even better news is that you can flash it without Windows. Just download the BIOS image from the Asus website, copy it onto a FAT formatted USB stick, insert that, go into the firmware (hit F2 on the splash screen) and start the flash program from there.

Flat | Top-Level Comments Only

We can find the BIOS update here : http://support.asus.com/download/download_item_mkt.aspx?model=UX21E I'm waiting the update for UX31E http://support.asus.com/download/download_item_mkt.aspx?model=UX31E

Thanks for the tip!

This... might not just be an ASUS thing. I have seen similar behavior on a certain HP in my possession.

Also, random, but why the hell would the thermal cutoff temp change based upon the power source? *BOGGLE*

Maybe the assumption that while battery powered it may be on your lap rather then a desk, and not wanting to risk burning users. Heat == Power too thou.

Bad assumption; I often use a plugged-in laptop in my lap.

One possibility: you typically unplug a laptop before tossing it in a case and going somewhere.

You should emphasize that this has to be FAT USB stick. Trying to use NTFS partition when flashing from BIOS can brick your laptop. This is what I did actually ;)

Hello,

I think I'm having the same problems with Lenovo Thinkpad X120e. After some stress and CPU heat the system goes bonkers with thermal shutdown. Needs to cool down an hour perhaps before everything works again. Pretty lame stuff. I took some vids about this:

First, the thermal shutdown occuring in Windows:
http://www.youtube.com/watch?v=rfhoUFQ1iSE

Second, live Linux (SystemRescueCD) dying in udev activation phase:
http://www.youtube.com/watch?v=ChJCQy5bS0o

Regards,
Mr. Janne Paalijarvi

I get a very sudden power cut out on my UX31e, either when it's been doing things for a while or when I yank the power plug out while it's running. I'll try the firmware upgrade too but yes it seems to be a problem on the ux31e as well. Thanks for posting this, it was very helpful.

I've upgraded to the latest BIOS (214) for my UX31E and it still powers off when unplugged and under a CPU load.

I also have a UX31E, and it has started to randomly shut off when on battery power. I recently installed the latest bios, 214, and it has not helped. I am running Ubuntu 12.04 LTS. I have tried all of this things found around this URL https://help.ubuntu.com/community/AsusZenbook

...but it still is acting up. Any help from anyone would be greatly appreciated.

Fixing Asus UX21e unexpected power off

Good news

Thanks

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FAT, but never NTFS

Same problems with Lenovo Thinkpad X120e I guess

same on UX31e

Latest BIOS (214) for UX31E still doesn't fix the issue

Re: Latest BIOS (214) for UX31E still doesn't fix the issue