Bug#757419: xrandr: Shows DVI-0 as connected to a non-existant monitor

[Facundo Gaich <facugaich@gmail.com>]

Package: x11-xserver-utils
Version: 7.7+3
Severity: important

Dear Maintainer,

I have a dual monitor setup with my Radeon HD 5770: a 1920x1080 one connected
through HDMI and a 1050x1680 one connected through DVI. I have them setup as
primary and secondary respectively, and everything was working fine on 7.7+2.
After I updated to 7.7+3, my desktop was still working as intended until
I launched once again the Displays configuration tool of Gnome 3.12, at which point
my configuration broke (my primary monitor lost signal and I had to do a full
power cycle to get to Displays again and fix it).

Trying to repair it, I discovered xrandr is now showing a 1024x768 monitor on
my other DVI port (DVI-0) which has nothing connected to it:

Screen 0: minimum 320 x 200, current 2970 x 1680, maximum 8192 x 8192
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected primary 1920x1080+0+235 (normal left inverted right x axis y axis) 598mm x 336mm
    1920x1080     60.00*+  50.00    59.94    30.00    25.00    24.00    29.97 23.98
    1920x1080i    60.00    50.00    59.94
    1680x1050     59.88
    1280x1024     75.02    60.02
    1440x900      74.98    59.90
    1280x960      60.00
    1360x768      60.02
    1280x800      59.91
    1152x864      75.00
    1280x720      60.00    50.00    59.94
    1024x768      75.08    70.07    60.00
    832x624       74.55
    800x600       72.19    75.00    60.32 56.25
    720x576       50.00
    720x480       60.00    59.94
    640x480       75.00    72.81 66.67    60.00    59.94
    720x400       70.08
DVI-0 connected (normal left inverted right x axis y axis)
    1024x768      60.00
    800x600       60.32 56.25
    848x480 60.00
    640x480 59.94
DVI-1 connected 1050x1680+1920+0 left (normal left inverted right x axis y axis) 473mm x 296mm
    1680x1050 59.95*+
    1600x1000 60.01
    1280x1024 75.02
    1440x900 59.90
    1280x960 60.00
    1152x864 75.00
    1152x720 59.97
    1024x768 75.08 60.00
    832x624 74.55
    800x600 75.00 60.32
    640x480 75.00 60.00
    720x400 70.08

I was able to "turn off" this unknown device through Displays.

I am using the radeon driver, I'm not sure if it could be a bug in there,
since xrandr --listproviders shows:

Providers: number : 1
Provider 0: id: 0x59 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 4 associated providers: 0 name:radeon

Thank you,
Facundo

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'testing-updates'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.14-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages x11-xserver-utils depends on:
ii  cpp          4:4.9.1-1
ii  libc6        2.19-7
ii  libice6      2:1.0.9-1
ii  libx11-6     2:1.6.2-2
ii  libxaw7      2:1.0.12-2
ii  libxcursor1  1:1.1.14-1
ii  libxext6     2:1.3.2-1
ii  libxi6       2:1.7.4-1
ii  libxmu6      2:1.1.2-1
ii  libxmuu1     2:1.1.2-1
ii  libxrandr2   2:1.4.2-1
ii  libxrender1  1:0.9.8-1
ii  libxt6       1:1.1.4-1
ii  libxxf86vm1  1:1.1.3-1

x11-xserver-utils recommends no packages.

Versions of packages x11-xserver-utils suggests:
pn  cairo-5c        <none>
pn  nickle          <none>
ii  xorg-docs-core  1:1.7-1

-- no debconf information