On Sun, Feb 28, 2010 at 02:27:19PM -0500, Kevin O'Connor wrote:
On Thu, Feb 25, 2010 at 08:36:11AM +0200, Gleb Natapov
On Wed, Feb 24, 2010 at 11:34:17PM -0500, Kevin
> On Wed, Feb 24, 2010 at 11:59:26AM +0200, Gleb Natapov wrote:
> > Shouldn't we make CONFIG_S3_RESUME_VGA_INIT=1 by default. Otherwise
> > console doesn't work on Linux after resume.
> As far as I can tell, a real BIOS does not call the video bios on
I don't think it should be enabled by default.
Googling "Run VGA Bios if S3 Resume" suggest that there are real BIOSes
run video bios on resume.
Though, the presence of a bios option seems to indicate that always
running the vga rom may not be a good idea.
Or it may indicate that there are BIOSes that always run VGA Bios on
resume, but we can provide similar option that will be passed on qemu
I don't see
how resume can work otherwise for
I don't know either - this topic has me confused.
May be because it can't
:) Here is the same problem with real HW:
ACPI spec is
clear though (section 15.3):
It is never for me :(
Functional device configuration. The BIOS doesn't
configure/restore context of functional devices such as a network
interface (even if it is physically included in chipset) or interrupt
controller. OSPM is responsible for restoring all context of these
devices. The only requirement for the hardware and BIOS is to ensure
that interrupts are not asserted by devices when the control is
passed to OS.
That is for the devices that are under OSPM control. VGA console in text
mode is hardly under OSPM control. When graphics is in use the device
driver is responsible to restore device state, but generic vga driver
cannot know how to restore internal state of different HW. This is the
reason Windows doesn't allow S3 when vga driver is used.
Also, I've read through the PCI specs, and I
haven't seen anything
that indicates a VGA BIOS should support being run from S3 resume. As
such, I'm not confident that a generic VGA BIOS wont write to memory
(corrupting the resume state) if it is run.
We should definitely audit our VGA BIOS
for such things. Also moder VGA
BIOS should use PPM for memory allocation no?
It would be nice to know what the "auto" option that some BIOS' have
for "Run VGA Bios if S3 Resume" does. I wonder what they look at to
determine whether or not to run the vga bios.