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Re: Radeon HD 3470 dual monitors on Squeeze



On Sat, 05 May 2012 09:05:35 -0400, Rob Owens wrote:

> I've been trying to get dual monitors to work on my Squeeze system.
> Originally I was using both the onboard video and an additional video
> card.  Now I have two monitors hooked up to the same video card (thanks
> to a cheap craigslist purchase).
> 
> When I begin booting, both monitors give me a display.  But when the
> boot process gets to the point where text display changes (framebuffer
> turning on?) one monitor goes blank and I cannot get it working again,
> even when logged into a GUI.

I'd first try to use "xrandr" and see how it manages. This is the guide I 
use when I have to play with the tool:

https://wiki.ubuntu.com/X/Config/Resolution#How_to_setup_a_dual_monitor

Debian "X-patrol" team :-) has a also a good guide:

http://pkg-xorg.alioth.debian.org/howto/use-xrandr.html

Depending on the DE/WM you are using, you can also configure this from a 
GUI utility (at least both GNOME and KDE do have one).

> Both monitors work properly with Knoppix 6.4.4.  I tried using the
> Knoppix xorg.conf, but that did not work.  Here are some differences
> between Squeeze and Knoppix:
> 
> 				Squeeze		Knoppix
> kernel:			2.6.32-5	2.6.37
> xserver-xorg-video-radeon:	1:6.13.1-2	1:6.13.2-1 
> libdrm-radeon1:		2.4.23-0.0	2.4.23-1 
> radeontool:			none		1.6.1-1
> 
> I don't know if the above differences are important or not.

Mmm, "radeontool" is an (sic) "utility to control ATI Radeon backlight 
functions on laptops" so I guess that having this installed or not won't 
make any difference.

> Any ideas why one monitor always goes blank in Squeeze?

If you want to use a static xorg.conf file, you can try to define a 
xinerama setup from there. First, ensure the xserver has loaded the 
extension correctly:

sm01@stt008:~$ grep -i xinerama /var/log/Xorg.0.log
(II) Initializing built-in extension XINERAMA

And then try to add the required stanza... IIRC, I had to Google a bit to 
find a working configuration file for my dual-head nvidia card, but you 
can find many samples out there, for instance:

https://help.ubuntu.com/community/XineramaHowTo#ATI

Hint: keep your xorg.conf file as small as possible.

Greetings,

-- 
Camaleón


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