I have a similar problem. If I install the fglrx or fglrx-update proprietary ATI Radeon driver, I'm able to log in but Unity doesn't load. Removing the proprietary driver fixes the issue.
This is the output of lspci -v | grep vga
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Madison [Radeon HD 5000M Series] (prog-if 00 [VGA controller])
Please let me know if there is any other information you need.
I have a similar problem. If I install the fglrx or fglrx-update proprietary ATI Radeon driver, I'm able to log in but Unity doesn't load. Removing the proprietary driver fixes the issue.
This is the output of lspci -v | grep vga
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Madison [Radeon HD 5000M Series] (prog-if 00 [VGA controller])
Please let me know if there is any other information you need.