On 02/08/11 00:26, Alexander Graf wrote:
> The new ISA infrastructure checks for potential irq sharing bugs on
> interrupt lines, because usually irq lines on isa can't be shared.
>
> The PREP spec however mandates that the irq lines for both IDE ports
> are shared and according to Aurelien this also used to work just fine.
>
> So let's add a way to enable this sharing again, so we don't introduce
> unnecessary regressions over older versions of Qemu.

Had a patch for that, got shoot down for reasons I don't remember, 
attached for reference.  It basically allows IRQ sharing in case the two 
devices sharing the IRQ are of the same kind.  In that case you usually 
have a single guest driver handling both devices and IRQ sharing works 
most of the time.

I don't mind much which approach we take ...

cheers,
   Gerd