Re: USB pass through into Mac OS 9.x with qemu-system-ppc

[Howard Spoelstra]

On Tue, Feb 16, 2021 at 4:42 PM Howard Spoelstra <hsp.cat7@gmail.com> wrote:
>
> On Tue, Feb 16, 2021 at 3:48 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
> >
> >   Hi,
> >
> > > Please find another pcap file attached. This one stems from an attempt
> > > to pass through a midi device when running qemu-system-ppc with Mac OS
> > > 9.2 in macOS host.
> >
> > Ah, yes, I remember now.  Problem is that the usb stick is plugged into
> > a high-speed port (usb2) on the host but passed as full-speed device
> > (usb1) to the guest.  That works in some cases, but is not guaranteed
> > to work.  usb_host_speed_compat() tries to catch some of the
> > incompatible cases.  The usb-storage incompatibility slips through
> > because the incompatibility is specific to the mass storage protocol.
> > Specifically the wMaxPacketSize is 64 for usb1 and 512 for usb2.
> >
> > Seems fedora deals better with the situation ...
> >
> > take care,
> >   Gerd
> >
>
> Hi Gerd,
>
> Thanks for looking into this. It looks to me that the usb storage
> device nicely reports endpoints 1 and 2 when asked, but that the host
> only ever communicates with endpoint 1.
> Is that the issue you refer to, or might that be libusb related?
>
> Can this also explain that other (non-mass-storage) devices cannot be
> passed through successfully ?
>
> Best,
> Howard

Hi Gerd,

Thanks for the explanation. I've been successful in passing through an
USB 2.0 stick into Mac OS 9.x when connected to a real USB 1.1 hub in
a old Apple keyboard. This at least gives some perspective to connect
other devices as well.

So we can consider this quest finished ;-)

Best,
Howard