I confirm that the bug appears to be fixed in Linux Kernel 2.6.39
I installed the Ubuntu mainline kernel v2.6.39-oneiric and you also need fgrlx 2:8.850 (you can use the Ubuntu-X ppa).
Tested on Lenovo Y560 Tested about 3 reboots without AC plugged in - it seams to work.
I confirm that the bug appears to be fixed in Linux Kernel 2.6.39
I installed the Ubuntu mainline kernel v2.6.39-oneiric and you also need fgrlx 2:8.850 (you can use the Ubuntu-X ppa).
Tested on Lenovo Y560
Tested about 3 reboots without AC plugged in - it seams to work.