Re: [Qemu-devel] [PATCH v2 07/11] versatile_pci: Implement the correct PCI IRQ mapping

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 26 March 2013, Peter Maydell wrote:
> 
> On 26 March 2013 10:54, Arnd Bergmann <arnd@arndb.de> wrote:
> > Yes, very good.  We will probably introduce sparse irq support on
> > versatile in the near future, and then the value we write into the
> > PCI_INTERRUPT_LINE field will become arbitrary from qemu's point
> > of view, but I will make sure that we fix the interrupt mapping
> > in the kernel at the same time so we always fall into the
> > "s->broken_irq_mapping = false;" case.
> 
> Yeah, as long as you avoid the number 27 you're ok :-)

Good point. I guess we'll have to keep using a legacy domain for
versatile then.

> > We also need to find a way to make the new kernel work with
> > an old qemu, and I think we can do that by using the versatile-dt
> > board type with a PCI device node that sets all four lines to
> > 27, while using the actual interrupt lines for the default
> > versatile device tree.
> 
> Personally I'd be happy for you to just say "needs a new QEMU".
> The broken QEMU is missing so much (including working memory
> windows) that I think it would be a pain to get the kernel to
> cope with it.

But it was working earlier, so I'd definitely try not to break
if at all possible. A lot of people use the verstatile qemu
model to run kernels and I would not want to deal with the
complaints I'd get if we break those. Using a separate dts
file seems easy enough.

	Arnd