From: Wolfram Sang <wsa@the-dreams.de>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] i2c-designware: always clear interrupts before enabling them
Date: Fri, 17 May 2013 10:31:42 +0200 [thread overview]
Message-ID: <20130517083139.GC17056@katana> (raw)
In-Reply-To: <1368442471-7582-1-git-send-email-mika.westerberg@linux.intel.com>
On Mon, May 13, 2013 at 01:54:30PM +0300, Mika Westerberg wrote:
> If the I2C bus is put to a low power state by an ACPI method it might pull
> the SDA line low (as its power is removed). Once the bus is put to full
> power state again, the SDA line is pulled back to high. This transition
> looks like a STOP condition from the controller point-of-view which sets
> STOP detected bit in its status register causing the driver to fail
> subsequent transfers.
>
> Fix this by always clearing all interrupts before we start a transfer.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Applied to for-current, thanks! Added stable, too.
WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Mika Westerberg
<mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 1/2] i2c-designware: always clear interrupts before enabling them
Date: Fri, 17 May 2013 10:31:42 +0200 [thread overview]
Message-ID: <20130517083139.GC17056@katana> (raw)
In-Reply-To: <1368442471-7582-1-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
On Mon, May 13, 2013 at 01:54:30PM +0300, Mika Westerberg wrote:
> If the I2C bus is put to a low power state by an ACPI method it might pull
> the SDA line low (as its power is removed). Once the bus is put to full
> power state again, the SDA line is pulled back to high. This transition
> looks like a STOP condition from the controller point-of-view which sets
> STOP detected bit in its status register causing the driver to fail
> subsequent transfers.
>
> Fix this by always clearing all interrupts before we start a transfer.
>
> Signed-off-by: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Applied to for-current, thanks! Added stable, too.
next prev parent reply other threads:[~2013-05-17 8:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-13 10:54 [PATCH 1/2] i2c-designware: always clear interrupts before enabling them Mika Westerberg
2013-05-13 10:54 ` Mika Westerberg
2013-05-13 10:54 ` [PATCH 2/2] i2c-designware: add Intel BayTrail ACPI ID Mika Westerberg
2013-05-17 8:31 ` Wolfram Sang
2013-05-17 8:31 ` Wolfram Sang [this message]
2013-05-17 8:31 ` [PATCH 1/2] i2c-designware: always clear interrupts before enabling them Wolfram Sang
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