I have Ubuntu 16.04 installed under Hyper-V Generation 2 VM with secure boot disabled. (Installed from mini.iso, if that matters. x86_64)
I found that there was a problem long ago (14.04) about fixed small screen resolution.
I tried the fix proposed in various thread, namely, added a line to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=hyperv_fb:1680x1050"
I also installed
dmesg shows that this command line is indeed passed to the kernel. (Cannot copy it because of the non-working copy-paste buffer between host and guest.)
The module, however, is not loaded (after boot,
lsmod shows no sign of
hyperv_fb manually doesn't change the screen resolution.