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

[Jordan Crouse]

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.

> 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.

>   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.

Jordan
-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.