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Re: [Qemu-ppc] Debug logs for USB on MorphOS

From: BALATON Zoltan
Subject: Re: [Qemu-ppc] Debug logs for USB on MorphOS
Date: Mon, 21 Nov 2016 01:01:16 +0100 (CET)
User-agent: Alpine 2.20 (BSF 67 2015-01-07)

On Fri, 11 Nov 2016, BALATON Zoltan wrote:
For those interested in more details it seems that the pciusb.device driver finds the OHCI chip in QEMU but does not like it and does not claim or try to initialise it for some reason.

It wasn't too easy to find it but it turned out to be caused by a mismatch between what's emulated in QEMU and what OpenBIOS put in the device tree so when trying to access the config registers of PCI bus 1 MorphOS ended up using PCI bus 0 which of course returned an error. After this was fixed the USB controller is found but patches from BenH to fix the interrupt was also needed for it to work. Patches submitted to OpenBIOS and QEMU.

The usefulness of this activity may not be direct as MorphOS may not ever run
on) but the bugs found and fixed during this do help making the device models in QEMU more accurate and help running other OSes. I think some of the bugs fixed this way in OpenBIOS and QEMU also helped to get MacOS running so I like to believe there are at least some indirect usefulness of this.

MorphOS now has input but still lacks some way to output video (this still needs some work). But if other OSes had the same problem fixed here then this may fix the enabling of the bus master bit for some network cards so the patch added for that in OpenBIOS may not be needed now and fixing the interrupt may improve mouse or sound behaviour on MacOS. I haven't tested these, just verified that MacOS 9 and Linux still boots with these patches.


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