Completely ignore EDID for KMS, use user-supplied kernel param (video=)?
pmiscml at gmail.com
Mon Nov 22 20:02:59 PST 2010
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:
which suggested that it's possible, but I don't have any effect doing
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.
Paul mailto:pmiscml at gmail.com
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