[Xorg-driver-geode] Geode LX DDC freeze in emulator when executing OUTW 0x20

[Martin-Éric Racine]

On 12/24/07, Jordan Crouse <jordan.crouse at amd.com> wrote:
> On 24/12/07 14:31 +0200, Martin-Éric Racine wrote:
> > Issues that have been reported by end-users include:
> >
> > 1. Failure to switch back to virtual console using CTRL+ALT+Fx.
>
> This is a new failure that has come along on the heals of Bart's
> investigations.  I don't believe that anybody has had trouble with this
> prior to the last  few weeks.  Anyway, this is a well known issue related
> to VBE/int10, or rather, the lack of it.  Like I explained before, when
> switching back to a virtual VGA text console, we need to issue an int10 to
> put the screen back into the VGA mode it was in when we entered.  A
> crippled or broken int10 will act exactly like you have seen.
>
> Since we know that the VBE and/or the int10 is broken on a small subset
> of hardware and BIOS, then it follows that once Bart cured the hang
> for the DDC, that you would still have int10 breakage elsewhere.
>
> I want to be clear that this is not universal breakage across all Geodes -
> it seems to be localized to a small subset.

I want to be clear that it in fact does break across the board on
General Software BIOS and on LinuxBIOS - on both the GX and LX - as
verified by a number of people with a wide variety of Geode-based
products to test against.


> > 2. Failure to auto-configure on X core 1.3 and newer, shown as either:
> >   a) failed DDC falls back to 640x480 @ 4-bit.
>
> Again - this has been explained - no DDC only gives us a very small range
> of available modes, by design in the X core.  Autoconfigure by its very
> nature depends on DDC.  If you have no DDC then it doesn't help you very
> much.   Complaining to the X core team isn't likely to change this - the
> values they have chosen in lieu of DDC are sane given the real possibility
> of damaging hardware.

That's assuming that we don't have DDC. The point is moot since the
same AMD X.org breakage is noticed on hardware that has DDC - not just
on the ThinCan.


> >   b) complete system freeze.
>
> This has only been seeen on a subset of systems - it seems to be related
> to broken VGA BIOS - or at the very least, a broken interaction between
> the BIOS and the emulator.

Agreed.

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