Legacy windows 7 guest resolution problems

[qharley]

I have a legacy windows 7 guest that was cloned from a medical system for support simulation.
The resolution is stuck at 800x600, and the platform does not have access to normal windows settings to adjust the resolution.

I somehow have to force the resolution to 1280x1024. The original hardware has a monitor that only allows this resolution.
The software is not written in an adaptable way, and everything is hard scaled on the monitor, meaning that large parts of the display gets cut off.

I am also forced to use SeaBios since the original system was installed in legacy mode, and does not run in the UEFI bios.

Is there a way to force the VM using Seabios to use 1280x1024?

 

[leesteken]

Did you install version 0.1.137 of the VirtIO drivers: https://forum.proxmox.com/threads/there-are-bugs-in-pve8-2.152294/post-690446 ? Then the resolution should follow the client window size.

 

[qharley]

I have to log into the "Service" interface if the software to get access to the windows operating system settings, and unfortunately this is part of the window that is cut off. Perfect storm.
Is there another combination I can try to at least get into the OS to update the drivers?

 

[leesteken]

I have to log into the "Service" interface if the software to get access to the windows operating system settings, and unfortunately this is part of the window that is cut off. Perfect storm.
Is there another combination I can try to at least get into the OS to update the drivers?

Sorry, I have no experience with this. But since it is a VM, you do have the virtual equivalent of physical access, so anything is possible. Maybe boot another WIndows7 VM with the virtual disk of this VM attached and change or add files that way? Maybe search the internet for getting administrator access on Windows7 to start any software you like (and put on the filesystem)?

 

[qharley]

Thanks. I can get access to the files using a virtual liveCD boot. This means I have to force the windows OS to use the right resolution from within the VM itself, and there is nothing that can be done from proxmox?
Last thing I tried was to pass and EDID to the VM, but I could not get it to boot after adding the following line to the conf:

args: -device virtio-gpu-gl-pci,edid=on,edidfile=/var/lib/edid/1280x1024.bin

Let me see what it possible from within the VM...

 

[leesteken]

This means I have to force the windows OS to use the right resolution from within the VM itself, and there is nothing that can be done from proxmox?

I don't know, sorry. Maybe someone else here knows how to do that for SeaBIOS?

 

[qharley]

I found a solution. It was hard to convert the drive to GPT (for UEFI) because of the condition of the image.
In the end I recreated the raw image of the physical HDD using ddrecue, and this image could be converted to GPT using the standard windows recovery tools.

After this was done, I could use the UEFI bios, and force the resolution I wanted. Works perfectly.

I am still looking for a solution to non UEFI operating systems. We have a couple of older medical systems still running on Windows 98 - Yes, you read that right. I might need to force specific resolutions to those as well. For the time being we will run those on discrete hardware.