Re: [RFC] Reliable video POSTing on resume

[Ondrej Zary <linux-ZCIryABCsrmttCpgsWEBFmD2FQJk+8+b@public.gmane.org>]

Matthew Garrett wrote:
> On Fri, 2005-02-04 at 21:30 -0500, Jon Smirl wrote:
> 
> 
>>I suspect the problem in that case is a compressed VBIOS. Some laptops
>>compress the VBIOS and the system BIOS into a single ROM and then
>>expand them at power on. Sounds like this is not happening on resume.
>>To get around the problem copy the image from C000:0 before suspend to
>>a place in preserved RAM where wakeup.S can find it and then copy it
>>back to C000:0 on resume. To test for this checksum C000:0 before
>>suspend and after and see if it has changed.
> 
> 
> No, that's not what's happening. If you disassemble the code at
> c000:blah in a laptop, you'll often find that it jumps off to a
> completely different section of address space. During POST, that
> contains video BIOS. After POST, it may be something like USB boot
> support. Without reading it directly out of flash, it's not possible to
> recover that code.

I wonder how this can work:
a motherboard with i815 chipset (integrated VGA), Video BIOS is 
integrated into system BIOS
a PCI card inserted into one of the PCI slots, configured as primary in 
system BIOS

During POST, the PCI card BIOS is initialized. I boot Windows 98SE - 
then the onboard VGA initializes and I can use 2 monitors.
So either:
1. The driver can initialize the onboard VGA on its own (without VGA BIOS)
or
2. There is a way how to get the onboard VGA BIOS code from system BIOS


-- 
Ondrej Zary


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