A couple of days ago I upgraded my laptop, an Asus UL30A, from Ubuntu 10.10 Maverick to 11.04 Natty. Everything went fine. Unfortunately pretty much all of my special keys (backlight, volume, suspend, WIFI) stopped working after the obligatory reboot.
Investigation showed the following lines in syslog:
May 5 11:26:56 kirana kernel: [ 30.900537] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x0000000000000064) is beyond end of object (20110112/exoparg2-418)
May 5 11:26:56 kirana kernel: [ 30.900551] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f118), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
May 5 11:26:56 kirana kernel: [ 30.900565] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff8801376382f8), AE_AML_BUFFER_LIMIT (20110112/psparse-536)
May 5 11:26:56 kirana kernel: [ 30.900580] ACPI Error: Evaluating _BCM failed (20110112/video-365)
Typical ACPI errors you encounter way too often on laptops. Ubuntu 11.04 comes with kernel 2.6.38. Instead of wasting countless hours tracking the actual issue down I decided to check with the latest and greatest vanilla kernel first. That was 220.127.116.11 at the time of writing. I compiled using Ubuntu’s configuration as a template. The required commands where the usual (more or less the following):
cp /boot/config-2.6.38-generic .config
yes '' | make oldconfig
make bzImage modules
make INSTALL_MOD_STRIP=1 modules_install install
update-initramfs -k 18.104.22.168 -c
After a reboot everything was working fine again.
Of course you can use the Debian/Ubuntu way for building and installing the kernel. The point is: 22.214.171.124 just works.