I've had the same problem with hard lock-ups using the "ati" driver with a Radeon 9700pro on a clean install of dapper. It still froze up when I upgraded to edgy, no difference. The system completely locks up. Nothing ever appears in the logs, but the freezing is consistent. When I switched from the ati driver to the vesa driver every worked fine, video refresh sucked of course, but it worked. Switch back to the ati and I froze within 15min. Finally I just installed the fglrx driver from the xorg-driver-fglrx package which has been working fine.
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R300 ND [Radeon 9700 Pro] 01:00.1 Display controller: ATI Technologies Inc Radeon R300 [Radeon 9700 Pro] (Secondary) -- system freeze when using ati radeon 7000 with xorg "ati" driver https://launchpad.net/bugs/16873 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
