Re: [GIT PATCH] USB patches for 2.6.33-git

From: Linus Torvalds
Date: Mon Dec 14 2009 - 22:09:56 EST




On Mon, 14 Dec 2009, Linus Torvalds wrote:
>
> I'll double-check by reverting it from current -tip, but if you don't hear
> anything different from me, you can assume that that double-check
> succeeded and confirms that that commit really is the cause of my printer
> no longer working.

Confirmed.

With that commit reverted, everything works fine again. So it's definitely
a2582bd478c13c574d4c16ef1209d333f2a25935, although I have no idea _why_ it
causes problems.

One thing I note is that it literally changed semantics, as per the
comment in there. It used to be:

This walks the driver device list and returns a pointer to the interface
with the matching minor.

and after that it is

This walks the bus device list and returns a pointer to the interface
with the matching minor.

Notice the "driver device list" -> "bus device list" change.

Also notice that the minor number of my 'lp0' device is zero, so I could
easily imagine that some device without a driver at all or whatever will
have a zero there, and then it would return the wrong device entirely.

So I really think that commit is very suspect. Not matching against the
driver that we passed in looks like some total screwup.

But I don't know the code or the use. I do know that reverting it fixes
it.

Linus
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