Comment 38 for bug 586325

Created an attachment (id=34795)
dmesg (for comment #38)

> Can you disable the vesa fb driver in kernel configuration and see whether the issue still exists?

Without the vesa fb driver there no big difference, only the "vga=" kernel parameter doesn't work anymore. The display switches from text mode to higher resolution later when the i915 module is loaded.

Yesterday I had again the situation where I could NOT recover from a "bad mode" (0x49) to a working one. After running "xrandr --output DVI1 --mode 0x49" the monitor went to standby mode. Then I tried to revert to mode 0x43, which resulted in the "out of sync" pattern (see attached dmesg).

Intermediary result:
At least some modes which are shown by "xrandr -q --verbose" are "bad". Switching to these modes puts the monitor in standby mode. Sometimes it's possible to switch back to a working mode by blindly using the shell history. Other times this causes the "out of sync" pattern.

For the moment I'm not sure whether the problem can only happen with specific "bad modes" or also with other ones.

regards
Christian