Created attachment 39139 [details]
Both monitors are connected via DVI after a fresh reboot
When connecting my two identical Acer monitors with their VGA input (using a DVI-to-VGA adapter) the dual screen works and xrandr is capable of changing the resolution of both monitors independently.
But when connecting both screens to DVI-I input one monitor stays black saying "no signal" even if xrandr says that the screen is connected and at native resolution.
It seems that the video= option affects this, and changes the behavior when one monitor is connected to VGA while the other is connected to DVI input. If the option "video=DVI-I-x:1920x1080eD" is passed for both screens (DVI-I-1 and DVI-I-2) only the VGA one shows something while we expect only the DVI one to work and not the VGA (as stated here : ) . If no option is passed both work as expected.
EDID are parsed correctly and monitors are detected correctly as will be shown in the multiple xrandr outputs that will follow.
As discussed on IRC it is impossible to force the subconnector with xrandr so we can't test this way. But anyway the sub-connectors are selected correctly.
Created attachment 39140 [details]
xrandr state after disconnecting the right monitor
Created attachment 39141 [details]
xrandr state after reconnecting the right monitor and disconnecting the left one
Created attachment 39142 [details]
xrandr state after disconnecting the left monitor (no monitor connected)
Created attachment 39143 [details]
xrandr state when booting with one connector in DVI the other in VGA and the video= option
Created attachment 39144 [details]
xrandr state when booting with one connector in DVI the other in VGA and without the video= option
Created attachment 39145 [details]
xrandr state after changing the VGA connector with a DVI one
When booting without the video= option, with one DVI and one VGA, both screen work as expected, but if I replace the VGA by a DVI the screen stays black with "no signal".
It appears that this bug report has laid dormant for quite a while. Sorry we haven't gotten to it. Since we fix bugs all the time, chances are pretty good that your issue has been fixed with the latest software. Please give it a shot. (Linux kernel 3.10.7, xf86-video-nouveau 1.0.9, mesa 9.1.6, or their git versions.) If upgrading to the latest isn't an option for you, your distro's bugzilla is probably the right destination for your bug report.
In an effort to clean up our bug list, we're pre-emptively closing all bugs that haven't seen updates since 2011. If the original issue remains, please make sure to provide fresh info, see http://nouveau.freedesktop.org/wiki/Bugs/ for what we need to see, and re-open this one.
The Nouveau Team