Re: [Qemu-devel] Seabios dislikes -M isapc

[malc <av1474@comtv.ru>]

On Tue, 9 Feb 2010, Anthony Liguori wrote:

> On 02/09/2010 05:25 PM, Aurelien Jarno wrote:
> > On Wed, Feb 10, 2010 at 01:41:01AM +0300, malc wrote:
> >    
> > > On Tue, 9 Feb 2010, Natalia Portillo wrote:
> > > 
> > >      
> > > > Xenix is currently working (when copied from real hardware).
> > > > As well Interactive UNIX and some other non-DOS from 8086 and 286 era.
> > > > 
> > > > I'm not really sure that operating systems (specially the 8086 ones that
> > > > do
> > > > mmu functions in software) will be happy with the PCI bus present.
> > > > 
> > > > Same for first 386 operating systems (OS/2 2, UNIX, Xenix, so on).
> > > >        
> > > News to me that OS/2 worked.. I don't quite remember which version
> > > someone (you?) asked me to try on IRC a few years back, but it definitely
> > > didn't work.
> > > 
> > >      
> > I have got OS/2 warp working under QEMU a few years ago. I couldn't give
> > more details though, I just remember it was working nicely.
> >    
> 
> The problem with isapc is that it uses a different chipset (or rather, doesn't
> use a PCI chipset).  I think the current thinking with target-i386 config
> files is that while you should be able to customize the system, some of the
> core bits would always be there.  For instance, the PCI chipset, the APIC,
> etc.  These things are very tied to a platform.

APIC is almost as good as useless without ACPI and we have a switch to
disable that.

> 
> Firmware is really hard to implement if you have to deal with supporting
> multiple chipsets.
> 
> Also, if we don't have a workload that actually needs isapc, that suggests
> that there's no real way to test that isapc doesn't have non-ISA things creep
> into it.
> 
> Given that, I'm inclined to suggest that we mark isapc as deprecated, give
> people some time to comment on it, and then provided that we still don't think
> it's necessary, change isapc to simply use isa devices while still using a PCI
> chipset.

Not to comment, to give hard evidence that something is working with isapc
and doesn't otherwise, in which case it must stay.

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