On Mon, Nov 22, 2010 at 11:02 PM, Paul Sokolovsky pmiscml@gmail.com wrote:
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@60 param, also tried more conventional modes like 1024x768).
I'd appreciate any hints.
Assuming your laptop contains a radeon, the panel timing comes from a table in the vbios. The timing problem is most likely not due to an EDID problem, but to pll dividers that that panel doesn't like. Try booting with radeon.new_pll=0 on the kernel command line or try kernel 2.6.37.
Alex