[Bug 90246] New: Switching from Xorg to fglrx-updates and back loses 1 monitor

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Wed Apr 29 16:44:07 PDT 2015


            Bug ID: 90246
           Summary: Switching from Xorg to fglrx-updates and back loses 1
           Product: xorg
           Version: unspecified
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Driver/Radeon
          Assignee: xorg-driver-ati at lists.x.org
          Reporter: jas.61803 at gmail.com
        QA Contact: xorg-team at lists.x.org

Created attachment 115460
  --> https://bugs.freedesktop.org/attachment.cgi?id=115460&action=edit
screenshot of driver manager dialog box

hi, i just updated to Kubuntu 15.04.

in System Settings -> Driver Manager:

at first, i used the X.org Xserver -- AMD/ATI display driver wrapper from
xserver-xorg-video-ati (Recommended), and it recognized both my monitors.

but I thought I would try the "Video driver for the AMD graphics accelerators
from fglrx-updates", for faster performance, so I switched to this.

however (separate issue), those drivers seem to have problems (even without
compositor turned on) with Chromium (really messed up screen drawing on
Chromium browser), so I decided to switch back to the X.org Xserver AMD/ATI
display driver.

however, when I switched back from fglrx to X.org driver, now I have lost one
of my two monitors. The X.org driver now seems to see only 1 monitor.

this is interesting because when I first upgraded to 15.04, and was on the
X.org driver, it did see both monitors.  It was only in switching to fglrx and
back to X.org driver that I lost the 2nd (dell) monitor.

I have tried switching out and back to X.org again, to no avail.  The fglrx
drivers DO see and use the 2nd monitor, but the X.org wrapper driver no longer

My computer is a Dell Optiplex 990 (Bios revision A13)
Processor: 4 x Intel Core i5-2400 CPU @ 3.10GHz
Memory: 3.8GiB RAM
Kubuntu 15.04
KDE Plasma Version: 5.2.2
Qt Version 5.4.1
Kernel Version: 3.19.0-15-generic
OS Type: 64-bit

"lspci -v" output on the graphics controller:

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cedar
[Radeon HD 5000/6000/7350/8350 Series] (prog-if 00 [VGA controller])
        Subsystem: Dell Radeon HD 6350
        Flags: bus master, fast devsel, latency 0, IRQ 16
        Memory at d0000000 (64-bit, prefetchable) [size=256M]
        Memory at e1520000 (64-bit, non-prefetchable) [size=128K]
        I/O ports at 3000 [size=256]
        Expansion ROM at e1500000 [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: fglrx_pci

The two displays/monitors:
ASUS VW266 25.5" (1920x1200) (the one that is always on)
Dell P2213t 22" (1680x1050) (the one that only flgrx sees)
both connected to graphics adapter via a dual DVI cable

$ xrandr -q
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1600 x 1200, current 1600 x 1200, maximum 1600 x 1200
default connected primary 1600x1200+0+0 0mm x 0mm
   1600x1200      77.0* 
$ _


If, then, (still using the X.org driver), I switch the DVI cables to the
monitors, the result is now that the system sees both monitors, BUT

a) the two displays are showing duplicate desktops, NOT an extended desktop,

b) xrandr now looks like:

$ xrandr -q
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1400 x 1050, current 1400 x 1050, maximum 1400 x 1050
default connected primary 1400x1050+0+0 0mm x 0mm
   1400x1050      77.0* 
$ _

What is interesting is that neither xrandr is correct. The larger screen (SUS)
is 1920x1200 and the smaller screen is 1600x1050.

also, "kcmshell5 kscreen" sees only 1 display (when using X.org driver), and 2
(when using fglrx driver).

I am just guessing, but i have a hunch that what happens is that when using
System Settings -> Driver Manager, switching back to X.org driver somehow
forgets Screen 1, keeping only Screen 0, in the xorg.conf file, and so the
driver doesn't even look for a second Screen/monitor/display

Please let me know if there is anything I can add to this report.



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