[SeaBIOS] S3 resume is broken on QEMU

[Gerd Hoffmann]

  Hi,

>> I'm 99% sure that wont work.  Option roms have to be copied from PCI
> You 99% sure it wont work on real HW or on QEMU? IIRC QEMU puts vgabios
> into 0xc0000 directly.

That is looooooooooooooooong history, it went away about the same time
qemu switched from bochs bios to seabios.

These days seabios loads them from either pci rom bar or via fw_cfg.

> Windows is actually smart. It knows that it can support S3 resume on
> generic VGA so it does not allow you to do S3 suspend when one is in
> use. We managed to trick WindowsXP + cirrus to allow S3 suspend by DSDT
> magic, but after resume GUI is not usable. Still good enough for running
> WHQL. The only way S3 works on all Windowses is by using QXL device and
> driver that supports S3.

If you ask the linux graphics guys the situation is simliar on linux.
S3 without kms driver doesn't work reliably and isn't supported[1]. Only
difference is that linux doesn't enforce this by refusing to suspend
without kms.

cheers,
  Gerd

[1] summary of a longish discussion, don't remember where though.