Re: [Qemu-devel] [FYI 4/4] prep: Quickfix for ioport

[Andreas Färber]

Am 27.12.2010 um 01:11 schrieb Alexander Graf:

> Am 27.12.2010 um 00:28 schrieb Andreas Färber  
> <address@hidden>:
>
> > Am 14.12.2010 um 01:49 schrieb Andreas Färber:
> >
> > > Workaround the following error:
> > >
> > > qemu: hardware error: register_ioport_read: invalid opaque
> >
> > I found out that this is a conflict with i8042 registering I/O port  
> > 0x0092 in pckbd.c, too.
> > Not sure what the proper fix should look like - add some qdev  
> > property to ISAKBDState to disable the port?
>
> Well, why does the PREP board have its own mapping there in the  
> first place? It should be the same as a PC from a port pov, no?

Why does the i8042 controller have a System Control Port in the first  
place rather than the 'pc' machine? :)

The PReP spec v1.1 has a Special Port 0x0092 that includes two bits of  
significence - softreset and endian mode. So wherever the port is  
registered, the latter behavior is board-specific and does not match  
pckbd.c (A20 gate or HDD activity depending on bit numbering).

A similar issue arises between PReP machines: The ioport currently  
does not allow using a different opaque for reads and writes to the  
same address. So either we need to change ioport or create some  
inheritence/override mechanism for port behavior.

Andreas