desperately seeking "IgnoreEDID"

[Konstantin Svist]

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
>
>

Try using fglrx instead of radeon driver. It has much better support for
recognizing bad EDID. At least it works properly on my external monitor
(while radeon and radeonhd fuck up the resolution)

HTH