[Bug 13590] Dual-head fails with ati driver, appears related to 'crtc'

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Tue Dec 11 05:11:33 PST 2007


haraldme at gmail.com changed:

           What    |Removed                     |Added
                 CC|                            |haraldme at gmail.com

------- Comment #3 from haraldme at gmail.com  2007-12-11 05:11 PST -------
As reported on launchpad (https://bugs.launchpad.net/bugs/172601) I have a
rather similar problem, with the following setup:

  Dell Latitude D610 laptop
  2 external monitors, each capable of 1600x1200 (one connected via VGA, and
one via DVI)

Tormod Volden requested that I try with the latest version of the driver from
his PPA archive (xserver-xorg-video-ati 1:6.7.196+git20071210-0ubuntu0tormod),
and post the results/logs.

I had no better luck with this version than with prior versions from Ubuntu
Gutsy -- the external monitor that's being driven by CRTC 0 goes black (or
displays a monitor-generated warning that it's unable to display the signal it
gets, for the DVI-attached monitor) when I try to use its preferred mode, while
the monitor being driven by CRTC 1 works fine.  If I swap which external
monitor is being driven by which CRTC around, it's always the one driven by
CRTC 0 that's unable to display the preferred mode.

I tested this by running "xinit" from a text vt as root, and performing the
following commands in the resulting xterm:

# Initial output was on LVDS + DVI-0.

xrandr --output LVDS --off --output VGA-0 --auto
# Monitor LVDS went black, and monitor VGA-0 stayed black.

xrandr --output VGA-0 --off --output LVDS --auto
# Monitor LVDS came alive again.

xrandr --verbose -q > /tmp/xrandr-q.lvds+dvi
xrandr --output LVDS --off --output VGA-0 --auto
xrandr --verbose -q > /tmp/xrandr-q.vga+dvi
# Repeat to get copies of xrandr output.  Monitor VGA-0 still black.

xrandr --output LVDS --off --output VGA-0 --auto --mode 1280x1024
# Monitor VGA-0 now came alive, but with a non-optimal resolution.
xrandr --verbose -q > /tmp/xrandr-q.vga-reduced+dvi
# Capture more xrandr output

xrandr --output VGA-0 --off --output LVDS --auto
# Move back to LVDS, before quitting.

I'll attach my xorg.conf and the X log resulting from this exercise shortly;
let me know if there's other data you'd like me to collect.

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