desperately seeking "IgnoreEDID"

[Robert P. J. Day]

   i'm still fighting to get my WUXGA display laptop to ignore the  
EDID information coming back from a video device, so i simplified the  
problem and here's what's happening so far.

   i have a fresh install of f9 on an aging dell inspiron 9200 with a  
full WUXGA display, and i'm trying to drive a full-res WUXGA signal  
into an external video processing device that is (theoretically)  
supposed to be able to handle that.

   if i connect my laptop to an external full WUXGA flat-panel  
(Samsung) display, no problem -- the image is perfect,  
pixel-for-pixel, and full WUXGA on both laptop and external monitor.

   if, however, i connect the laptop to that external video device,  
that external device is (apparently) returning EDID information that  
claims to not be able to accept full WUXGA (even though it should be  
able to, allowing us to conclude that its EDID info is simply wrong  
and we'll have to fix that at some point.)  and doing that also forces  
my laptop down to a lower resolution.  argh.

   i figured that a simple solution is to just configure my laptop to  
ignore incoming EDID and keep driving the signal at full WUXGA, but i  
can't get that to work.  here's my change to /etc/X11/xorg.conf (text  
copied by hand as the laptop is not on the net):

   Section "Device"
     Identifier "Videocard0"
     Driver     "Radeon"
     Option     "IgnoreEDID" "True"   <-- added this
   EndSection

   as an experiment, i connected the laptop to a flat panel dell  
1280x1024 display to see what would happen, logged out, logged back  
in, and the Xorg log file contains the line:

   (**) RADEON(0): Option "OptionEDID" "True"

which i would have thought confirms the ignoring of incoming EDID, but  
i still get the same effect of having my laptop resolution dropped  
noticeably (in this case, to 1152x864, according to "xdpyinfo"),  
ostensibly to accommodate the decreased resolution of the external  
monitor.

   so,

   1) is there something else i should be trying to get my laptop to  
totally ignore the fact that it's connected to an external device that  
claims to not be capable of full WUXGA, and

   2) if i succeed in ignoring EDID with this test flat panel,  
obviously, the flat panel can't handle that (full WUXGA) signal so i'm  
not expecting to get a useful image, but is there a chance i could  
damage the flat panel?

   open to suggestions.

rday