[Xorg-driver-geode] X failure under LinuxBIOS

[Martin-Éric Racine]

On 1/29/08, Jordan Crouse <jordan.crouse at amd.com> wrote:
> On 28/01/08 12:05 +0200, Martin-Éric Racine wrote:
> > As the attached file shows, running "X -configure" fails on a Geode LX
> > booting from LinuxBIOS. This is against the current AMD driver 2.7.7.6
> > and X server 1.3 patched with Bart's x86emu fixes.
>
> I just did a quick run to verify that coreboot (LinuxBIOS) w/o VGA works.
> When you do X -configure, the only way that we can do into the stack trace
> listed below is if we find the string "IBM VGA Compatible" at 0xc001e in
> the physical space.  Thats usually a great indication that VGA is there.
> If for some reason, you have managed to get that string and not have VGA
> present, then it will blow up in a similar manner to what you are seeing.
>
> If the latter is the case, and you don't have VGA but somebody is writing
> that memory space (naughty!) then you need to find the offending code and
> flog it.  Alternatively, you can clear the VGA hole before leaving
> coreboot.
>
> If you do have VGA attached, then you'll need to follow Bart down the
> rabbit hole.

We build our LinuxBIOS with both VSA and VGA blobs.

Someone at work did a detailed tracing of the whole affair. In short:
LinuxBios does not provide INT15 and thus DDC does not work. Nothing
to do with VSA.

-- 
Martin-Éric Racine
http://q-funk.iki.fi