The problem also occurs with standard Ubuntu 10.10, on a Dell Inspiron 1521 with a Turion x64 and its integrated graphics so named Radeon 1250 or x690 (I believe). This has happened some time in each of the 6-monthly beta phases over the last 2+ years, so I'm not too worried, it just seems to be one of those compatibility issues between ATI graphics and the Linux kernel.
The problem also occurs with standard Ubuntu 10.10, on a Dell Inspiron 1521 with a Turion x64 and its integrated graphics so named Radeon 1250 or x690 (I believe). This has happened some time in each of the 6-monthly beta phases over the last 2+ years, so I'm not too worried, it just seems to be one of those compatibility issues between ATI graphics and the Linux kernel.