Hi,
I recently had black screen problems with QXL in 0.14.x that turned out to
actually be a Seabios bug due to the default 64MB vram QXL has.
It is a seabios issue indeed.
I suspect
this would hit 0.15.x builds too. If this is what you're hitting, then
reducing the vram to 32MB is a temporary workaround that should help, eg
-vga qxl -global qxl-vga.vram_size=33554432
There is a fixed seabios binary @ http://spice-space.org/download/seabios/
Patches are all upstream, so just fetching the latest seabios bits (git
master branch) and building yourself will work too.
cheers,
Gerd