Re: [Qemu-devel] [PATCH, RFC 3/4] prep: Fix duplicate ISA IDE IRQ

[Alexander Graf]

On 20.12.2010, at 07:37, Andreas Färber wrote:

> Am 14.12.2010 um 01:49 schrieb Andreas Färber:
> 
>> Calling isa_ide_init() twice with the same IRQ 13 fails:
>> 
>> qemu: hardware error: isa irq 13 already assigned
>> 
>> Use a different IRQ (14) for the second one to avoid this.
>> 
>> Signed-off-by: Hervé Poussineau <address@hidden>
>> Cc: Alexander Graf <address@hidden>
>> Signed-off-by: Andreas Färber <address@hidden>
> 
> The implied question behind "RFC" is, has this been a dormant bug in 
> ppc_prep.c or would this need to be fixed at ISA level (allowing two devices 
> to share the same IRQ) in isa-bus.c where the above error message is raised?

That depends on the hardware. Usually ISA can't share IRQs. There are some 
exceptions though, where ISA controllers have some built in magic to enable 
sharing along identical devices. Not sure which case we're looking at here, but 
having them separate is certainly the safe choice.


Alex