I'd just like to chime in and say this bug affects me too. I have a dell studio 1558 with a core i5 M450 and radeon HD 5400 (ish), and run ubuntu 12.10, but also had the same issue on 12.04. The problem never affected me prior to upgrading to 12.04. In addition, my computer sometimes freezes on startup (after the GRUB screen, but before the login screen, often without seeing the ubuntu logo at all, happening perhaps 1 in every 10 boots now); an issue I believe is related, as both started happening around the same time.
In agreement with other posts here, changing the brightness too quickly triggers a freeze, which is characterised in my case by the screen turning into changing, multicoloured rectangular blocks, sometimes with a mouse cursor (often enlarged) visible or semi visible. REISUB does not work, as with other users. On 12.04, I did not get multicoloured blocks on a freeze if I recall; just a blank screen. REISUB also does not work when my computer freezes on boot. Anyway, I'm looking forward to a fix for this too, so let me know if there is any information or output I can provide, or anything I can try, and I shall do so if possible :) Thanks, James -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1007765 Title: brightness adjusting crashes system To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1007765/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs