Completely ignore EDID for KMS, use user-supplied kernel param (video=)?

[Paul Sokolovsky]

Hello,

There're cases when EDID may be present, but be just severely (or
seemingly) broken. Is it possible to completely and unconditionally
ignore any EDID info for KMS, and instead use user-supplied parameters?
I googled the following message:
http://www.mail-archive.com/dri-devel@lists.sourceforge.net/msg46741.html
which suggested that it's possible, but I don't have any effect doing
it myself.

It's also very hard to diagnose these issues. For example, mode
selection is driven by EDID, but there're whole 0 occurances of that
string in kernel dmesg. Passing drm.debug=1 starts to dump some
internal registers, but still no hints which and why mode was selected.

My specific issue is that there's an LVDS (of MSI X410/X430 notebook)
which has right dimensions and refresh rate, but wrong, if not say
unrelated, clock settings. The end result is that there's tearing-off,
broken sync like on an old dying TV. More details are at
http://wwww.ubuntuforums.org/showthread.php?p=10120939 . That's on
2.6.35 (stock Ubuntu 10.10 kernel). I was able to set CVT timings on X
which gave stable picture, but no luck persuading kernel to do the same
(I used video=LVDS-1:1366x768M at 60 param, also tried more conventional
modes like 1024x768).

I'd appreciate any hints.


-- 
Best regards,
 Paul                          mailto:pmiscml at gmail.com