[Xorg-driver-geode] GeodeLX freeze with General Software BIOS saga continues

[Alan Cox]

On Fri, 11 Jan 2008 09:53:32 -0500
Bart Trojanowski <bart at symbio-technologies.com> wrote:

> * Alan Cox <alan at lxorguk.ukuu.org.uk> [080111 09:34]:
> > > This is bad because 0x20 is the PIC control register.  I believe that
> > > this cuts the kernels scheduler tick and nothing else can run after
> > > that.
> > 
> > If we are even using the PIC. The X86 emu should consider ports 0x00-0xff
> > as very suspect, and certainly block the port ranges 0x00-0x21,
> > 0x40-0x43, 0x50-0x53, 0x70-0x77, 0x81-0x8f, 0xa0, 0xa1, 0xc0-0xdf even if
> > correctly accessed rather than an emulation bug.
> 
> Alan,
> 
> would it be fair to consider those ports suspect on any x86 platform?
> Surely anything that has a BIOS needs to preserve the functionality that
> those ports provide.

Those ports are all suspect as they are things like the timer chip and
IRQ controller. If you touch those you will upset the OS. If stuff is
accessing them in the BIOS then X would need to grow some emulation.


Alan