Comment 26 for bug 989191

"Could someone with the problem try reproducing it with Windows?"

I reproduced the problem with Windows 7. Here's my test setting:

I reinstalled Windows 7 and some drivers and utilities (most importantly ASUS Power4Gear-Hybrid) from here:

http://www.notebook-driver.com/fi/asus/asus-zenbook-ux31e-win7-64bit-driver-utility/

First I didn' t get any crashes (same goes always some time with fresh install of Ubuntu). I tried to pull AC-cable off every now and then and with different amounts battery charge.

I used Jpcsp as test application (because it uses lots of resources, and always freezes Ubuntu if I try to run it without AC-cable). I didn't get any crashes, but I noticed that the emulator slows down every time I pull off the AC-cable, so I went to check Power options.

I found out that in On Battery -mode in ASUS Power4Gear-Hybrid's "High Performance"-battery plan the maximum processor state is set to 80% as default. I changed it to 100% (AC not connected, emulator still running) and immediately got the shutdown. After restarting I tried Windows 7's own High performance setting (maximum processor state 100%; I had to force ASUS Power4Gear-Hybrid to shut down before that, because it tries to overrun the battery plan every time I touch the AC cable). When I started the emulator (AC still not connected), Windows 7 froze. In that point I had only 30% of battery charge left. When I tried to restart Windows 7, I got immediate shutdown (probably because of low battery). Then I put AC cable back on, waited for some time for battery to charge and ran the emulator again (with about 50% charge). Everything worked untill I pulled AC cable off -> crash. I changed maximum processor state back to 80% and ran the emulator again. When I pulled off the AC cable, I didn't get crash. I repeated this about 10 times and still no crahes. Here's my conclusion:

The shutdown or freezing occurs in Windows 7 when:
- Processor state is over 80% and the AC cable is pulled off
- Processor state is over 80% and the AC cable is not connected
- Processor state reaches some point that's more than is needed to run grub but less than is needed to boot Windows 7, the AC cable is not connected and battery has less than 30% of charge

After I wrote this my heart was pounding when I last time pulled the AC cable off (Power4Gear-Hybrid's default "High Performance"-battery plan is currently active). As you can read this, you can see that I still didn't have any crash.