My EDID was going unrecognized until I added video=VGA-1:e

Some strange behavior from my xorg with Ubuntu 18.04:

I have a firmware file set up so that grub will load a firmware "helper" file for my hanns-g 24" monitor.

I put on a VGA extender SR from Gefen to test it out and for some reason it doesn't pass the EDID, which is ok because I've got the kernel parameter drm_kms_helper.edid_firmware.
(BTW the signal from the VGA extender looks pretty awesome for a long cable run).


For some strange reason, it didn't work until I added video=VGA-1:e (which is supposed to enable the VGA-1 output).

Until I added the parameter video=VGA-1:e I would get this dialog upon boot when it tried to restore my previous display settings:




$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.15.0-42-generic root=UUID=xxx-yyyy-zzzz ro drm_kms_helper.edid_firmware=VGA-1:edid/hannsg.bin drm_kms_helper.edid_firmware=VGA-1:edid/hannsg.bin video=VGA-1:e

Keen eyes will notice I put the drm_kms_helper.edid parameter in there twice by accident, I just left it in there, it doesn't seem to hurt anything. The last parameter on the line seems to take precedence.

I also tried drm_kms_helper.edid_firmware=VGA-1:edid/1920x1080.bin for one of the built-in edids which also worked, and gave ONLY the 1920x1080 resolution.


and running xrandr --verbose shows my EDID is getting read.


$ xrandr --verbose
Screen 0: minimum 320 x 200, current 3120 x 1920, maximum 8192 x 8192
VGA-1 connected primary 1920x1080+1200+510 (0x46) normal (normal left inverted right x axis y axis) 521mm x 293mm
Identifier: 0x42
Timestamp: 60227
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
EDID:
00fffffffffff etc.


It's pretty important that my system comes up properly on first boot because the monitor rotation seems to freak out the i915 driver with my dual monitor setup if I switch back and forth between monitor rotation and normal and I get all kinds of weird display corruption and flickering after that. If it comes up "clean" the display looks fine.