[Qemu-devel] seavgabios resolutions, win8

[Michael Tokarev <mjt@tls.msk.ru>]

I tried switching from plex/bochs vgabios to seavgabios,
and made this switch for qemu-1.7 package in debian, at
least to see how it goes.

And almost immediately got a complain that with new qemu
(which uses seavgabios not vgabios), windows VMs don't
support 1920x1080 resolutions anymore.

Almost immediately we cooked a patch which restored the
mode(s) in question, here it is:

--- a/vgasrc/bochsvga.c
+++ b/vgasrc/bochsvga.c
@@ -89,6 +89,9 @@
     { 0x18a, { MM_DIRECT, 2560, 1600, 16, 8, 16, SEG_GRAPH } },
     { 0x18b, { MM_DIRECT, 2560, 1600, 24, 8, 16, SEG_GRAPH } },
     { 0x18c, { MM_DIRECT, 2560, 1600, 32, 8, 16, SEG_GRAPH } },
+    { 0x18d, { MM_DIRECT, 1920, 1080, 16, 8, 16, SEG_GRAPH } },
+    { 0x18e, { MM_DIRECT, 1920, 1080, 24, 8, 16, SEG_GRAPH } },
+    { 0x18f, { MM_DIRECT, 1920, 1080, 32, 8, 16, SEG_GRAPH } },
 };

 static int is_bochsvga_mode(struct vgamode_s *vmode_g)

Should something like this be applied?

Of the same theme, there's a wishlist bugreport against vgabios in
Debian, to add a few more resolutions, http://bugs.debian.org/669114 --
it adds 2048x1536 resolution, which is also missing in seavgabios.

Also, vgabios 0.7 provided a few more resolutions, like 1280x768 and
1280x720.

I'm not sure I understand how list of modes is maintained/used in
seavgabios.  The above patch at least allows one of the very common
modes to be selected in windows clients.


And while at it, there's another bugreport against vgabios package in
Debian, see http://bugs.debian.org/685097 .  It looks like windows8
isn't happy with vgabios-provided modes and does not let to change
resolution at all, sticking at 1024x768.  That bugreport points to
a patchset, http://lists.xen.org/archives/html/xen-devel/2012-05/msg00260.html
(this is just one patch from it), which has been applied to xen copy
of vgabios to solve exactly this issue with win8, and reportedly it
works there.  It looks like something similar should be done in
seavgabios too, since with it, win8 guest is also stuck at the same
resolution.

Thanks,

/mjt