I recently installed a fresh copy of Ubuntu 15.10 on my laptop. Everything went fine right up to the moment when I had my first system boot. I logged in by typing the password as usual, like in the others previous versions but this time I had nothing to see but my cursor and just the wallpaper. I can t use the system at all, it just freezes at the purple screen. I am using a laptop with an intel pentium dual core processor and 6370m ati graphics card which worked in Trusty Tahr.
2 Answers
Add the parameter radeon.modeset=0 the to the end of the linux line before booting !
Highlight the Ubuntu menu entry -> press the "e" key -> add the parameter -> press F10.
To make this solution permanent add the parameter to GRUB settings /etc/default/grub.
You can do this as follows ... when not already installed before - install the package gksu.
Open a terminal and execute :
sudo apt-get install gksu
Then execute :
gksudo gedit /etc/default/grub
Add radeon.modeset=0 to this line : GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
that it reads : GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.modeset=0"
Then execute :
sudo update-grub
In case you have AMD Catalyst drivers installed - they have known issues with kernel 4.2.
There is a workaround fix in wily-proposed but it is recommended to wait until it is tested.
Use the open source radeon drivers in the meantime until the final Catalyst fix is released.
Uninstall the proprietary AMD drivers from a virtual console :
On login screen press Ctrl + Alt + F1 - enter user name and password and then execute :
sudo apt-get purge fglrx
sudo reboot
In this case first boot without adding the parameter to see whether it will work for you.
-
Thank you for your answer. Unfortunately none of the methods seem to work for me. After adding the parameter, it boots up having the same issue( purple screen and only cursor working). However, when I try to edit grub I get the following error: "(gksudo:1702): GTK-WARNING ** : cannot open display:" – Claudiu Daj Nov 02 '15 at 15:26
Or use kernel 4.1 which has long term support, it works perfectly with Catalyst on 15.10 ;) That's how i solved the same problem.

- 16