On Fri, Jan 20, 2012 at 04:23:15PM +0100, Gerd Hoffmann wrote:
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.
Ah yeah fw_cfg. How could I forget about it :) Still we know what our vgabios is doing so we can make sure it works. bochs bios had to be fixed to make S3 work too.
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.
Well it is obviously not :) Microsoft makes sure resume works if suspend is allowed.
S3 without kms driver doesn't work reliably and isn't supported. Only difference is that linux doesn't enforce this by refusing to suspend without kms.
If it isn't supported it should not be allowed. Why Linux graphics guys do not send patch that disables S3 on unsupported configurations? Did this come up in ?
But I want to understand their support statement a little bit better. Do you need kms driver for resume to be "supported" even if X is running? Because if X is not enough we may as well remove S3 from dsdt.
BTW does QXL have kms driver?
 summary of a longish discussion, don't remember where though.