Re: [PATCH 1/4] ide-pmac: media-bay support fixes

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Mon, 2008-06-23 at 16:41 +1000, Benjamin Herrenschmidt wrote:
> > Don't panic. It looks like it's something else in linux-next that's
> > changing some ifdef's in the media-bay code which is causing that.
> > 
> > I managed to pull linux next at the merge point with your tree and
> > things apply. I'll use that to test.
> 
> Ok, it doesn't work properly. It gets error trying to register
> the IDE device. Booting with a CD drive in and no disk in the drive
> gives the log below.
> 
> I've verified that it works without your patches. If I apply only patch
> 1, it doesn't build due to some wrong construct in the probe code. I've
> hand fixed it, but then I hit a BUG_ON in ide_probe_port() (line 773).
> 
> mediabay boot time messages (before IDE probing) are:

BTW. I didn't debug more today as I ran out of time but I'll do more
tomorrow.

On a side note, we need to change the way the mediabay stuff works. I've
started writing a pata_macio (ie. libata variant of the driver) a while
ago that I need to kick myself into finishing one of these days, and it
will want something different than having the mediabay code poke into
the IDE layer directly :-)

My current though is to add a media bay notification callback to the
macio_device structure (the pci variants of the device are never hooked
up on a media bay) and move the state query function to the macio core,
the media bay driver being then responsible for calling into the macio
core to update the state.

I still have to sort out some interesting locking issues vs. state
changes around driver probe() but I think that's the way to go. Thus,
the drivers/ide driver can do it's old ide core hackery locally and the
libata variant do what is needed for libata locally too.

It's been a bit low on my todo list as Apple stopped making machines
with hotswap mediabays something like 8 years ago :-) The two I have
still working are pretty scary old things and one of them is almost
falling apart..

Cheers,
Ben.