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SubjectRe: [PATCH] USB host: Fix lockdep warning in AMD PLL quirk
On Wed, Apr 06, 2011 at 11:16:07AM -0400, Alan Stern wrote:
> On Wed, 6 Apr 2011, Joerg Roedel wrote:
> > amd_chipset.probe_count++;
> > /* probe only once */
> > if (amd_chipset.probe_count > 1) {
> > spin_unlock_irqrestore(&amd_lock, flags);
> > return amd_chipset.probe_result;
> > }
>
> The counter really should be a bool: Has the chipset already been
> probed or not? After all, nobody cares how many times this routine was
> called.

The quirk function needs a re-structuring anyway. The code-path is not
very straight-forward and readable. But for this fix I tried to keep the
changes small.

>
> > + spin_unlock_irqrestore(&amd_lock, flags);
>
> This code now contains a bug: You incremented the probe_count _before_
> doing the probe. If another thread calls this routine right now, it
> will get an incorrect result.
>
> Fixing this up should be fairly easy.

Okay, I will do. Thanks for the feedback.

Joerg

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