Re: [patch 2.6.28-rc2] at91_mci: workaround lockdep

[Nicolas Ferre]

David Brownell :
> On Tuesday 28 October 2008, Peter Zijlstra wrote:
> > On Mon, 2008-10-27 at 14:26 -0700, David Brownell wrote:
> > > From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
> > >
> > > Lockdep reported a problem in the at91_mci driver ... in this case, the
> > > issue is with lockdep, not with the driver. ...
> > >
> > > When __flush_dcache_aliases() returns -- inlined into flush_dcache_page(),
> > > above -- it re-enables IRQs ... since that evidently may only be called with
> > > IRQs enabled.  That's OK since the (unshared) IRQ handler doesn't ask for IRQs
> > > to be disabled.   Except ... that lockdep went and disabled them, then went on
> > > to complains about the breakage *it* caused!
> > >
> > > Workaround: depend on LOCKDEP=n ... 
> > In all previous such cases it was deemed the IRQ handler should deal
> > with whatever it gets.
>
> In which case I'll wait until someone changes that IRQ handler (or that
> ARM MM utility, or lockdep), and give up using AT91 platforms for sanity
> testing kernel changes; lockdep is important, when it doesn't lie.

Changing IRQ handler in this driver... seem to be a big work.

Well, Dave, I tend to acknowledge your patch above as the IRQ for MCI is 
indeed a dedicated line (no need for IRQF_SHARED).

Are you ok with this ?

Regards,
--
Nicolas Ferre

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