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	Tue, 23 Jun 2015 07:13:14 -0400
Date: Tue, 23 Jun 2015 12:13:10 +0100
From: Dave P Martin <Dave.Martin@arm.com>
To: Stefan Wahren <stefan.wahren@i2se.com>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Robin Murphy <Robin.Murphy@arm.com>,
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	<linux-arm-kernel@lists.infradead.org>,
	Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>,
	stable <stable@vger.kernel.org>
Subject: Re: [PATCH] serial/amba-pl011: Disable interrupts around TX softirq
Message-ID: <20150623111310.GB3645@e103592.cambridge.arm.com>
References: <1434635669-23367-1-git-send-email-Dave.Martin@arm.com>
 <416658426.177742.1434791378036.JavaMail.open-xchange@oxbsltgw09.schlund.de>
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On Sat, Jun 20, 2015 at 10:09:37AM +0100, Stefan Wahren wrote:
> 
> > Dave Martin <Dave.Martin@arm.com> hat am 18. Juni 2015 um 15:54 geschrieben:
> >
> >
> > pl011_tx_softirq() currently uses spin_{,un}lock(), which are not
> > sufficient to inhibit pl011_int() from being triggered by a local
> > IRQ and trying to re-take the same lock. This can lead to
> > deadlocks.
> >
> > This patch uses the _irq() locking variants instead to ensure that
> > pl011_int() handling for a given port is deferred until any
> > pl011_tx_softirq() work for that port is complete.
> >
> > Fixes: 734745caeb9f serial/amba-pl011: Activate TX IRQ passively
> > Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> > Tested-by: Robin Murphy <robin.murphy@arm.com>
> > Cc: stable <stable@vger.kernel.org> # 4.1
> >
> 
> I also get info messages about inconsistent lock state on my mx28 board,
> after applying the patch the messages disappeared.
> 
> Tested-by: Stefan Wahren <stefan.wahren@i2se.com>

Thanks for the confirmation.

Cheers
---Dave


From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave.Martin@arm.com (Dave P Martin)
Date: Tue, 23 Jun 2015 12:13:10 +0100
Subject: [PATCH] serial/amba-pl011: Disable interrupts around TX softirq
In-Reply-To: <416658426.177742.1434791378036.JavaMail.open-xchange@oxbsltgw09.schlund.de>
References: <1434635669-23367-1-git-send-email-Dave.Martin@arm.com>
 <416658426.177742.1434791378036.JavaMail.open-xchange@oxbsltgw09.schlund.de>
Message-ID: <20150623111310.GB3645@e103592.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Sat, Jun 20, 2015 at 10:09:37AM +0100, Stefan Wahren wrote:
> 
> > Dave Martin <Dave.Martin@arm.com> hat am 18. Juni 2015 um 15:54 geschrieben:
> >
> >
> > pl011_tx_softirq() currently uses spin_{,un}lock(), which are not
> > sufficient to inhibit pl011_int() from being triggered by a local
> > IRQ and trying to re-take the same lock. This can lead to
> > deadlocks.
> >
> > This patch uses the _irq() locking variants instead to ensure that
> > pl011_int() handling for a given port is deferred until any
> > pl011_tx_softirq() work for that port is complete.
> >
> > Fixes: 734745caeb9f serial/amba-pl011: Activate TX IRQ passively
> > Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> > Tested-by: Robin Murphy <robin.murphy@arm.com>
> > Cc: stable <stable@vger.kernel.org> # 4.1
> >
> 
> I also get info messages about inconsistent lock state on my mx28 board,
> after applying the patch the messages disappeared.
> 
> Tested-by: Stefan Wahren <stefan.wahren@i2se.com>

Thanks for the confirmation.

Cheers
---Dave