desperately seeking "IgnoreEDID"

[Roger Heflin]

Robert P. J. Day wrote:
>   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
> 
> 

You might try UseEDID as:
         Option      "UseEDID" "FALSE"

And see if it works any better.

                         Roger