Dual link on X1250 radeonhd git head fails

Adam J. Richter adam at yggdrasil.com
Wed Mar 19 23:51:50 PDT 2008

On Mon, Mar 17, 2008 at 02:42:40PM +0100, Matthias Hopf wrote:
> Current git of radeonhd should support dual link DVI as well, though
> this is untested ATM.

	I just tried the radeonhd git head (pulled minutes ago) on a
30 inch 2560x1600 HP lp3065 monitor, and the screen is black with the
green LED flashing.  This same screen displays BIOS messages, lilo
text and the character mode linux console fine, as I think there is
some built in video stretching done in character mode (for example, in
character mode, my 1920x1200 monitor always claims to be receiving a
1920x1200 signal rather than 640x480 or something similar that one
would normally associate with character mode).  xrandr, correctly
describes the video modes for my 1920x1200 monitor on the VGA cable
and the 2560x1600 monitor on VGA, and indicates that 2560x1600 is
selected, and the virtual screen size is expanded to 2560x1600.  So, I
think this is a mode setting issue and not some misconfiguration on my

	My new lp3065 can select between three dual-link DVI input
cables, so I should be able to plug it into an nvidia card for now to
use it immediately while still being available to test new changes
through a cable connect to my AMD motherboard.  So, if anyone wants me
to try a patch and report results, I am happy to do so when I have time.

	Also, if anyone would like to point me to the relevant page
numbers of the recently released X docs for the rs690 in
http://www.x.org/docs/AMD/ for enabling dual link, I may be able to
try to work on this myself during the weekend.  I had previously
skimmed AMD's recently released documents but didn't immediately find
a bit to set to activate dual link.

Adam Richter

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