[coreboot] Geode db800 vs Wyse S50
oliver at schinagl.nl
Tue May 25 17:49:49 CEST 2010
On 05/25/10 16:11, Peter Stuge wrote:
> Oliver Schinagl wrote:
>>> You can do some things also without VSA. VSA is used to create
>>> virtual PCI devices for among other things sound and graphics.
>>> However, a native graphics driver such as the one in libpayload or
>>> xf86-video-geode may not need VSA to drive the graphics hardware.
>> I suppose I won't even need VSA? I intend on booting Linux only; so
>> as long as that works, i'd be happy?
> I think Linux will need VSA to be happy though.
There isn't a way to excract the VSA from a running linux on the system
So if I would use setpci; i'd be actually changing things within the
VSA; Hmm ... I was hoping I could use setpci to enable the IDE controller...
>> How does this virtual PCI device thing work?
> The VSA blob installs a System Management Mode handler which traps
> instructions that normally access PCI hardware, and they are instead
> handled by the VSA code, which responds like PCI hardware would.
Gonna read through that...
>> Or what should I imagine in that area? My mind draws a blank. I just
>> know that usually your video chips is connected to the PCI bus. How
>> would this all work on a virtual PCI bus?
> The Geode is a different architecture, it uses a different bus called
> GeodeLink, and provides PCI compatibility on top of that.
> Drivers that understand GeodeLink directly (such as the X graphics
> driver) do not need the PCI compat stuff.
Kinda makes sense, as the GPU is built in anyway; what about Net/Audio
devices? They would have regular PCI connections on the chips so the
Geode would need some form of PCI connector for those devices and
connect that then tot he geodelink? Probably in the pdf so i'll read
that first :)
>> If using seabios; would I need the VSA to draw the boot menu
>> selection screen (assuming there exists such a thing even :)
> Actually it's even worse. You need a VGA BIOS for the CPU, and I
> don't know if there is a free one available. There was a GSoC project
> last year to create one, and there were patches that worked on Geode
> LX, but I'm not sure about the status on GX2.
> Those patches were for the SeaBIOS VGA BIOS "subproject" and I don't
> know for sure if VSA is needed, but I would guess that it is.
How about extracting the bios using /dev/iomem + /dev/mem such as
mentioned ont he Obtaining a VGA Bios wiki page?
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