Ubuntu 14.04 to 16.04 Radeon HD 5770 but basic display functionality does not work

Question

Lets start by saying that i wish I had read this before and I wish that on an upgrade prompt Ubuntu would warn about major compatibility issues such as - http://www.omgubuntu.co.uk/2016/03/ubuntu-drops-amd-catalyst-fglrx-driver-16-04

however based on this page - https://help.ubuntu.com/community/RadeonDriver my gpu should work just fine with the 16.04 drivers

So, I have just upgraded from 14.04 to 16.04 and my two screens are not detected and mirroring instead of extending the desktop.

$ xrandr -q
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 400, current 1280 x 1024, maximum 1280 x 1024
default connected primary 1280x1024+0+0 0mm x 0mm
   1280x1024      0.00* 
   1280x960       0.00  
   1152x864       0.00  
   1024x768       0.00  
   800x600        0.00  
   640x480        0.00  
   720x400        0.00

Also the resolution is too low and monitor instead of the two connected are detected as default. On IRC #ubuntu I have got the suggestion to configure xorg and looking at the guide at http://zeroset.mnim.org/2013/01/07/dual-head-monitor-setup-on-ubuntu-linux-with-xorg-and-radeon/ I see that xrandr is supposed to detect the monitors well to attempt a Xorg config.

From Xorg log - Segmentation fault

[  5786.223] (**) ModulePath set to "/usr/lib/xorg/modules"
[  5786.223] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[  5786.223] (WW) Disabling Mouse0
[  5786.223] (WW) Disabling Keyboard0
[  5786.223] (II) [KMS] drm report modesetting isn't supported.
[  5786.223] (EE) 
[  5786.223] (EE) Backtrace:
[  5786.223] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x5581fdedc5ce]
[  5786.223] (EE) 1: /usr/lib/xorg/Xorg (0x5581fdd2a000+0x1b6959) [0x5581fdee0959]
[  5786.223] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7fcc5f18c000+0x354a0) [0x7fcc5f1c14a0]
[  5786.223] (EE) 
[  5786.223] (EE) Segmentation fault at address 0x0
[  5786.223] (EE) 
Fatal server error:
[  5786.223] (EE) Caught signal 11 (Segmentation fault). Server aborting
[  5786.223] (EE) 
[  5786.223] (EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org

I dont need 3D acceleration and would like to fix the problem instead of downgrading to 14.04. What else can I try?

Answer 1

In my case it was not a problem with compatibility between drivers/cards and kernel. I had nomodeset in my grub config blocking radeon driver from loading.

to check grub config see this article - how-to-configure-the-grub2-boot-loaders-settings/

So in my experience after looking at this problem try the following

check modprobe config to make sure the correct driver is blacklisted/or not,under /etc/modprobe.d/ files and make sure radeon is not blacklisted

check grub as described above and remove the nomodeset option bearing in mind that this might cause other problems

Answer 2

I was in the exact same position with both my monitors mirroring each other. Thanks to Bizmate, I checked under etc/modprobe.d, and I found a file called "fglrx-core.conf".

The contents of "fglrx-core.conf" were as follows:

# This file was installed by fglrx

# Do not edit this file manually

blacklist radeon

alias fglrx fglrx

alias radeon off

alias lbm-radeon off

I made a copy of the file and named it "fglrx-core.bak" and deleted the original "fglrx-core.conf" file.

After rebooting, I immediately noticed that the login field was only on one of my monitors and knew that my desktop was once again extended instead of mirrored. After logging in, I was able to set up my extended desktop and rearrange the monitors as is normally done in the GUI's System Settings>Displays.
"fglrx-core.bak" seems to have been the remnant of fglrx that had remained and continued to blacklist the default radeon driver after upgrading to 16.04 from 14.04. Especially since I also upgraded to 16.04 from 14.04 without first uninstalling fglrx as is recommended.