Comment 70 for bug 586325

Thanks for those logs. The interesting part appears here, when you attempt to switch resolutions:
…
Jun 9 08:31:07 c399693 kernel: [ 60.921838] [drm:drm_mode_debug_printmodeline], Modeline 27:"1920x1200" 60 154000 1920 1968 2000 2080 1200 1203 1209 1235 0x48 0x9
Jun 9 08:31:07 c399693 kernel: [ 60.921844] [drm:drm_mode_debug_printmodeline], Modeline 31:"" 0 65000 1024 1048 1184 1344 768 771 777 806 0x0 0xa
…

Modeline 31 is not on the list of probed modelines from the EDID, but is almost the same as the 1024x768 modeline. Similarly, when trying to switch back it switches to another modeline which isn't listed in the EDID probe, but is almost the same as the 1920x1200 modeline.

I'll poke through the code to see what might be happening here.