[PLUG] External monitor remains black

[John Jason Jordan]

On Sun, 28 Nov 2010 05:35:28 -0800
Michael Rasmussen <michael at jamhome.us> dijo:

>On Sat, Nov 27, 2010 at 10:12:06PM -0800, John Jason Jordan wrote:
>> I have a Thinkpad T61 with nVidia Quadro NVS 140M running Fedora 14
>> x86_64 (Gnome). After several days of googling and fiddling I
>> managed to get the laptop display (normally 1680x1050) to run at
>> 1400x1050, using the nouveau driver.
> 
>> I also have a Viewsonic VG2021m (borrowed from Keith Lofstrom) which
>> can do 1400x1050 as its native preferred resolution. It is plugged
>> into the VGA output on my T61. I have tried dozens of things, but the
>> Viewsonic remains black. 

>Since you don't state what the dozens of things are I feel compelled
>to ask the obvious: did you cycle through the <Fn><F_ Key for the
>external display> settings pressing keys at each step?  
>
>This normally puts the laptop display system into three states:
>    On board LCD on,  external off
>    On board LCD off, external on
>    On board LCD on,  external on
>
>If you've chosen the correct F_ key your onboard LCD will turn off
>during one stage of this testing. 

Thanks for the suggestion. I knew that the Fn-F7 key is supposed to
wake up an external monitor, and I had tried it. I was unaware that it
actually cycles. Just now I tried it and the laptop screen did go black
at one point, so it is working. And at one point the Viewsonic powered
off and gave me a "no signal" message. The next keypress turned the
Viewsonic back on. But its screen remains black. So the Fn-F7 keys are
apparently working as expected. 

Among the many things I have tried is connecting to a different
monitor. I have a desktop computer as well, which is connected to a
monitor that can do 1680x1050. Its behavior is the same as the
Viewsonic, that is, there is a faint backlight and I can turn it on and
off, but no screen. At least I know that the problem is not hardware.

I have also tried different resolutions on both screens. And I have
tried setting the external display to be to the right, bottom, top,
and left. Xrandr sees both monitors, says they are connected, and
displays the correct resolutions and timings. The Xorg.0.log does not
indicate any error messages. And I have also tried booting with the
external monitor connected, and also not connected, which made no
difference. If I boot without it connected and then connect it after X
is up and running it becomes immediately visible.

At this point I'm wondering if it's a bug in the nouveau driver.