Debian 9 resolution incorrect on external display after OSX sleep/wake

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EricL17

Bit poster
I have a very basic installation of Debian 9. I use it in full-screen on one of my external displays (3440x1440 USB-C/DisplayPort). While in use during the day it works fine -- and has for many years.

I've noticed an issue since upgrading to Parallels 15. When I wake up my computer in the morning, my Debian VM is placed on the correct display, but it is using a 1680x1050 resolution. I need to toggle full-screen before Parallels realizes that it should be using all the pixels.

This didn't happen with 14 and older versions. I recall, with the older installs, there being a couple seconds where things would flicker and Parallels would automatically figure out that the resolution would change -- and it would eventually end up with the full 3440x1440 resolution automatically.

I assume this change is due to the new video driver under Linux.

I haven't been able to reproduce this outside of my "go to bed and wake up in the morning" test, so it's a little tricky to test out fixes. I'm guessing that I can use xrandr to force the correct resolution -- I'll test that out tomorrow. But can't the tools just do this automatically like they've done before?

Thanks
 
Update: this did reproduce after lunch. From within the VM,
Code: 
xrandr -s 3440x1440
fixes it. Maybe I could schedule some job to do this automatically, but it's still sort of silly that that would be necessary.
 
Edit: my xrandr trick only *sort of* fixes it. The display scales to the full resolution, but Debian/X is still sort of confused. Xorg gets really laggy and I get artifacting if I try to use more than about 2/3 of my screen. There isn't anything obvious in Debian journalctl or the OSX Console logs. Any idea of other logs I can look at?

Again -- all goes back to normal if I toggle the OSX full-screen.
 
Really very happy to say, your post is very interesting to read. I never stop myself to say something about it. You're doing a great job.Keep it up TelltheBell
 
This didn't happen with 14 and older versions. I recall, with the older installs, there being a couple seconds where things would flicker and Parallels would automatically figure out that the resolution would change -- and it would eventually end up with the full 3440x1440 resolution automatically.

Did you find solution for this?
 
No, no solution yet. I hit this state probably a couple times a day and it's really frustrating.

Is there some command-line tool I can run from the guest to force parallels to resynchronize the resolution?
 
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