I've got an ultrabay battery for my thinkpad r51. If I boot my kernel with it, i can see both batteries in /proc/acpi/battery/BAT{0,1}. Then, I can hotswap ultrabay battery for a cdrom (hdc=cdrom boot param makes it work, though it's a kluge too, it'd be good to have some way for re-scanning IDE devices) then back and everything still works (CD works, /proac/acpi/battery/BAT1 works when battery is swapped back). But if I load my kernel without the extra battery plugged in, then add the battery, it won't show up in /proc/acpi/battery/BAT1, only the main (BAT0) will be there. Any way to tell the kernel to rescan the ACPI stuff? The process if plugging the battery itself generates an ACPI event which I can handle and execute smth. It'd be also great to know if there's any way of telling the kernel to rescan IDE devices - the "hdc=cdrom" way is not very pretty (there's idectl 1 rescan (uses hdparm, actually), but it needs the /dev/hdc device, and udev won't create it if there was no cd drive on kernel boot).
I might should have replied your email in acpi-dev, but I can't access bugzilla till today, so I can't point out the exact tract for this issue. Ok, Could you please test the patch in bug 2884? *** This bug has been marked as a duplicate of 2884 ***
Yes, these kernel parameters make it work for me. Will the battery driver be fixed so that there would be no need for them?