Re: [PATCH 5/5] opticon: Fix resume logic

From: Johan Hovold
Date: Wed Oct 07 2009 - 12:03:28 EST


On Tue, Oct 06, 2009 at 11:23:31PM +0100, Alan Cox wrote:
> On Tue, 6 Oct 2009 23:12:17 +0200
> Oliver Neukum <oliver@xxxxxxxxxx> wrote:
>
> > Am Dienstag, 6. Oktober 2009 17:06:57 schrieb Alan Cox:
> > > Opticon now takes the right mutex to check the port status but the status
> > > check is done wrongly for the modern serial code, so fix it.
> >
> > As Alan Stern noticed, it seems like we have an ab-ba deadlock here
> > between open and resume regarding pm_mutex and port->mutex.
>
> Oh well I guess someone with hardware will have to fix that.
>
> Do we actually need a separate pm_mutex anyway ?

The pm_mutex is actually not aquired during open (and Alan Stern just
confirmed that), so there is no dead-lock with port->mutex.

/Johan

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