Resolution switch leads to the screen/image being corrupted

[Diego Viola]

I am currently using QEMU on a Arch Linux host, the guest OS is also Arch Linux.

The QEMU version is currently 2.12.0-2 packaged by Arch Linux, the command line I'm using to fire an Arch VM is:

$ qemu-system-x86_64 -enable-kvm -hda archlinux.qcow2 -m 4G -smp 4

The problem I'm currently having is, after firing the VM and running startx I want to change the resolution to the native resolution, which is 1366x768 on my ThinkPad T450, however, after changing the resolution the image on the guest gets corrupted and it's impossible to see anything.

At this point I can only turn off the VM. The only workaround I found is to start the VM with -vga virtio.

The problem in this case occurs with -vga std which is the default video driver.

[Diego Viola (diego-viola-deactivatedaccount)]

Switching the resolution with -vga std was working fine before, I'm not sure on which version it started having this issue, but it should be on a recent version.

I use the intel i915 drivers on the host OS.

[Francisco de la Peña (fdelapena)]

Hi Diego,

It seems this is a known limitation[1] because horizontal width is not a multiple of 8, try 1360x768 as the nearest resolution, which works for me on guests not supporting QXL drivers.

Regards.

[1] Proposed patch from 2013: https://lists.gnu.org/archive/html/qemu-devel/2013-03/msg02732.html

[Diego Viola (diego-viola-deactivatedaccount)]

Hi Francisco, thanks for your quick reply.

I've tried `xrandr --output Virtual-1 --mode 1360x768' with -vga std and I also get a corrupted image.

I'm attaching a screenshot of what the screen corruption looks like after changing the resolution.

Thanks.

[Thomas Huth (th-huth)]

The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience.

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]