On 07/02/16 21:34, Peter Saisanas wrote:Do you happen to have an xorg.conf? if so, please remove it. Xorg should probe for your screens and not need an xorg.conf.It shouldn't need any kernel parameters passed.... But stranger things have happened!Thanks for your help Peter No. There's no xorg.confPlease post your xorg.0.log, just curious to see if the edid is read correctly.Attached as a text fileFYI, I tried it with a Quadro FX4500 and a flashed GeForce 7800 and D.H. seemed to work. I used a Dell 24" LCD @ 1900x1200 together with an old Philips 20" @ 1680x1050 and it worked... For me anyway.... I should have an old GeForce 6600 laying around. I believe you mentioned this is GPU you have? If you like, I can try it out when i get a spare moment as well to see if it works on my end.That would be great but it seems strange it wouldn't just work, particularly as both xfce and xrandr see both monitors. What is odd is that in the xfce display settings there are options to activate and make both monitors master and to discover monitors but the "apply" button is greyed out.It may end up being something specific with the GeForce 6600.Regards Clive Hi Clive, Thought I should create a specific thread with your issue. I just tested a spare GeForce 6600 I had laying around and the dual head display behaviour is definitely not working. Whereas with the Quadro FX4500 it works fine (xrandr and D.H.). So it is an issue specifically affecting the GeForce 6600 (maybe others as well). As you described with the 6600, it seems to detect the second display head, (i.e. it reads the EDID correctly) but there is no digital output when connecting a second display via the DVI-I interface (digital). I don't have a spare DVI-A to VGA adapter, but just curious if it may work better with a VGA display on the second head? I have been able to force a digital output on the second head by appending the following to the kernel command line: append="video=DVI-I-2:D" However it then seems to think the second head is a DFP (LVDS) LCD panel (i.e. a laptop). Unfortunately, also using the mentioned appended kernel command, the second head display is quite bad, (wrong colours, incorrect geometry and graphical corruption). But the output does get enabled. So in other words, I don't think it is an xrandr issue at all. Perhaps the issue is is either the nouveau driver doesn't configure the second head correctly for this particular GPU family (GeForce 6600 or NV43) or the Apple OEM FCODE rom used in the GeForce 6600 is has incorrect parameters configured in the DCB? Link below to understand what the DCB is: ftp://download.nvidia.com/open-gpu-doc/DCB/1/DCB-4.0-Specification.html I know that others may say "but it works fine in OSX"... However Apple has written their own drivers so they may have their own workaround implemented directly in their own driver. This is a bit of a shame as this particular GPU is the most common one supplied with the Powermac G5 11.2 (DC) machines... If the issue is the DCB in the FCODE rom, there may be a magical appended kernel command to workaround the problem. Otherwise, perhaps we can try to patch a GeForce 6600 GPU VGA BIOS and load it from a file so nouveau uses this patched VGA BIOS instead of extracting it from the original FCODE rom from the OF device tree. Of course, this is on the assumption that the D.H. issue is indeed because of the incorrect DCB parameters in the GeForce 6600 Apple OEM FCODE rom and not nouveau specifically with NV43. Any takers? Regards, Peter |