On Thu, Feb 25, 2010 at 08:36:11AM +0200, Gleb Natapov wrote:
On Wed, Feb 24, 2010 at 11:34:17PM -0500, Kevin O'Connor wrote:
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 resume.
As such, I don't think it should be enabled by default.
Googling "Run VGA Bios if S3 Resume" suggest that there are real BIOSes that 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.
I don't see how resume can work otherwise for non-GUI setups.
I don't know either - this topic has me confused. The ACPI spec is clear though (section 15.3):
Functional device configuration. The BIOS doesn't need to 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.
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.
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.