From: Oliver Neukum <oliver@neukum.org>
To: Johan Hovold <jhovold@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Alan Cox <alan@linux.intel.com>,
Alan Stern <stern@rowland.harvard.edu>,
greg@kroah.com, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org
Subject: Re: [PATCH 5/5] opticon: Fix resume logic
Date: Wed, 7 Oct 2009 18:01:58 +0200 [thread overview]
Message-ID: <200910071801.59423.oliver@neukum.org> (raw)
In-Reply-To: <20091007155602.GB12396@localhost>
Am Mittwoch, 7. Oktober 2009 17:56:02 schrieb Johan Hovold:
> 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@neukum.org> 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.
This is currently true, but will no longer be true if autosuspend is
implemented for this driver.
Regards
Oliver
next prev parent reply other threads:[~2009-10-07 16:01 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-06 15:05 [PATCH 0/5] tty_port_open Alan Cox
2009-10-06 15:06 ` [PATCH 1/5] tty_port: add "tty_port_open" helper Alan Cox
2009-10-06 15:06 ` [PATCH 2/5] tty_port: coding style cleaning pass Alan Cox
2009-10-06 15:06 ` [PATCH 3/5] usb_serial: Use the shutdown() operation Alan Cox
2009-10-06 15:06 ` [PATCH 4/5] usb_serial: Kill port mutex Alan Cox
2009-10-07 5:02 ` Oliver Neukum
2009-10-07 16:03 ` Alan Stern
2009-10-07 16:10 ` Oliver Neukum
2009-10-07 16:34 ` Alan Stern
2009-10-07 16:46 ` Alan Cox
2009-10-07 17:23 ` Alan Stern
2009-10-07 18:25 ` Alan Cox
2009-10-07 18:52 ` Alan Stern
2009-10-07 20:56 ` Oliver Neukum
2009-10-07 21:02 ` Alan Cox
2009-10-07 21:34 ` Alan Stern
2009-10-08 13:43 ` Oliver Neukum
2009-10-08 14:58 ` Alan Stern
2009-10-08 15:27 ` Oliver Neukum
2009-10-08 16:58 ` Alan Stern
2009-10-08 20:06 ` Alan Stern
2009-10-08 20:40 ` Oliver Neukum
2009-10-08 21:19 ` Alan Cox
2009-10-08 21:31 ` Alan Stern
2009-10-08 22:31 ` Alan Cox
2009-10-08 11:37 ` Oliver Neukum
2009-10-06 15:06 ` [PATCH 5/5] opticon: Fix resume logic Alan Cox
2009-10-06 21:12 ` Oliver Neukum
2009-10-06 22:23 ` Alan Cox
2009-10-07 15:56 ` Johan Hovold
2009-10-07 16:01 ` Oliver Neukum [this message]
2009-10-07 15:56 ` Alan Stern
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