Tuesday, June 12, 2012

Backlight control causes hard reboot on Macbook Pro

Since installing Fedora on my aged first-generation Macbook Pro I was plagued by intermittent reboots. They mostly occurred during the boot process, while logging into KDE, and—less often— when the system was up and running. No need to mention this was a disaster and it pretty much cured me from using a file system that deems a fsck-tool of no great import.

At least for the latter crash-type, I was able to pin-point the culprit: it was the black-light control. Whenever KDE dimmed the panel there was a solid chance the system would reboot—no kernel panic, no stopping. Not even kdump would break its fall. Sure enough, disabling dimming would cure that.

Display dimming can be disabled in KDE's «Engery Saving Settings»

Now I am waiting for the next crash during reboot before blacklisting the «apple_bl» kernel driver. But maybe the Linux kernel 3.4 that ships with Fedora 17 has mended this issue already. Lets wait and see.