Re: [Qemu-devel] [Qemu-ppc] [PATCH] adb: change handler only when recognized

[Benjamin Herrenschmidt]

On Tue, 2016-08-09 at 03:31 +0200, BALATON Zoltan wrote:
> 
> > Because PowerBooks do (or rather a PMU-simulation of ADB) and MacOS
> > doesn't care. If ADB is in the device-tree, it will use it. It makes
> > things easier to support multiple combinations especially when
> > "comparing" things for debug.
> > 
> > Additionally, USB doesn't work well in OpenBIOS at this point ;-)
> 
> In what way? Keyboard works. What else is needed?

Doesnt' work for me half of the time, I haven't dug into why yet.

> > Also, I have some evil plan to change the way ADB autopoll works in
> > Qemu so that the devices signal the PMU when they want to talk. That
> > will avoid having yet another 30-something HZ timer ticking in qemu,
> > and in that regard will probably be more efficient (read: slows down
> > the emulator less) than OHCI.
> 
> OK, this is a really nice thing and justifies having an ADB bus. (This 
> would also likely fix mouse problems seen by others.)

Possibly ;-) The tracking in OS 9 at least is still done by a timer
inside MacOS itself. With my latest ndrv it's running at 30Hz. I'm
looking at maybe doing some kind of paravirt hack to make it adaptative
on whether there is actual movement on the cursor, but that's for later.

> > Why not ?
> 
> Just thought emulating all the additional details for Powerbook power 
> management might be difficult. But if you're willing to go there I won't 
> stop you. :-) Obviously you understand this very well so maybe it's not 
> that difficult for you.

Well, I wrote most of the corresponding Linux code so it's mostly a matter
of swapping that knowledge back into my brain from lossy long term storage
and finding all the MacOS 9 bugs along the way :-)

> > > 
> > >  Here's an (untested) patch for
> > > switching to using USB keyboard and mouse instead of ADB unless USB is 
> > > disabled. (The device tree should be changed accordingly in OpenBIOS.) 
> > > Not 
> > > sure if this is helpful.
> > 
> > Don't bother just yet, as I said, I am reworking all of that code. I will
> > probably just create various -machine options so you can chose what bits
> > and pieces you want to put togeher, ie, CUDA, PMU, with or without ADB,
> > which machine model string to expose to the OS etc...
> 
> Cool, looking forward to it. Thanks for all the great stuff you did for 
> this and keep it up.

Cheers,
Ben.