Created attachment 116715 [details]
I have two video cards, each connected to one monitor via DVI.
The first card is a Poulsbo (using the gma500_gfx kernel module), the second is a displaylink (using the udl kernel module). They both have an entry in /dev/dri.
My xorg.conf is just:
Identifier "Video Device"
Option "ModeDebug" "true"
The X server does see both cards (e.g., "xrandr --listproviders" shows the two cards), but only sees (and sets up) the output of the Poulsbo ("xrandr" only lists the DVI-0 output).
The Xorg.log (attached) mentions a DVI-1-0 output connected on the displaylink card, but for some reason it doesn't try to get the EDID and "xrandr" can't use it (e.g. if I try "xrandr --output DVI-1-0 --auto" it tells me there's no such output).
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