Re: [PATCH v2] hw/usb/vt82c686-uhci-pci: Use ISA instead of PCI interrupts

[BALATON Zoltan]

On Mon, 11 Oct 2021, Gerd Hoffmann wrote:
> On Tue, Oct 05, 2021 at 03:12:05PM +0200, BALATON Zoltan wrote:
> > This device is part of a superio/ISA bridge chip and IRQs from it are
> > routed to an ISA interrupt set by the Interrupt Line PCI config
> > register. Change uhci_update_irq() to allow this and use it from
> > vt82c686-uhci-pci.
>
> Hmm, shouldn't this logic be part of the superio bridge emulation?

But how? The ISA bridge does not know about PCI and PCI does not know 
about ISA. UHCI is a PCIDevice and would raise PCI interrupts. Where and 
how could I convert that to ISA interrupts? (Oh and ISA in QEMU is not 
Qdev'ified and I don't want to do that as it's too much work and too much 
to break that I can't even test so if an alternative solution involves 
that then get somebody do that first.) This patch puts the irq mapping in 
the vt82xx specific vt82c686-uhci-pci.c which in the real chip also 
contains the ISA bridge so in a way it's part of the superio bridge 
emulation in that this uhci variant is part of that chip model.

Regards,
BALATON Zoltan