Dear Christopher, Thanks for your suggestion. I've done a few more experiments before and after updating the BIOS (to the latest version (4105 07/01/2013). Here are the results.
1. Old Bios. Mageia 3 + Fglrx driver => Worked fine 2. Old Bios, Kubuntu Trusty (installed yesterday, fully updated), Open-source (Radeon) driver. => No CPU hang. However, I did have a problem with video-modelines being auto-detected wrongly, (resulting in the monitors showing out-of range. I've since fixed that manually with xrandr --addmode and will shortly file a bug on it, but this is what set me off on the path of trying the binary drivers). 3. Old Bios, Trusty, and the fglrx driver (both fglrx and fglrx-update, as per https://help.ubuntu.com/community/BinaryDriverHowto/AMD ) => CPIU hang. 4. Old Bios, Utopic alpha, and open-source driver => No cpu hang (but the modeline problem still present) 5. New Bios, Utopic, open-source driver => No cpu hang (but the modeline problem still present) 6. New Bios, Utopic, fglrx CPU hang again (see dmesg attached) Best wishes Richard ** Attachment added: "Dmesg output" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1338177/+attachment/4147183/+files/dmesg.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1338177 Title: BUG: soft lockup - CPU#0 stuck for 23s! [Xorg:1295] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1338177/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
