From: Michael Jones <michael.jones@matrix-vision.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>,
Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
linux-media@vger.kernel.org, sakari.ailus@iki.fi
Subject: Re: [RFC/PATCH 1/2] v4l: Add generic board subdev registration function
Date: Fri, 20 May 2011 09:52:38 +0200 [thread overview]
Message-ID: <4DD61DC6.10909@matrix-vision.de> (raw)
In-Reply-To: <201105200929.33226.laurent.pinchart@ideasonboard.com>
On 05/20/2011 09:29 AM, Laurent Pinchart wrote:
[snip]
>> I had an issue when tried to call request_module, to register subdev of
>> platform device type, in probe() of other platform device. Driver's
>> probe() for devices belonging same bus type cannot be nested as the bus
>> lock is taken by the driver core before entering probe(), so this would
>> lead to a deadlock.
>> That exactly happens in __driver_attach().
>>
>> For the same reason v4l2_new_subdev_board could not be called from probe()
>> of devices belonging to I2C or SPI bus, as request_module is called inside
>> of it. I'm not sure how to solve it, yet:)
>
> Ouch. I wasn't aware of that issue. Looks like it's indeed time to fix the
> subdev registration issue, including the module load race condition. Michael,
> you said you have a patch to add platform subdev support, how have you avoided
> the race condition ?
I spoke too soon. This deadlock is staring me in the face right now,
too. Ouch, indeed.
[snip]
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next prev parent reply other threads:[~2011-05-20 7:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-19 18:34 [RFC/PATCH 1/2] v4l: Add generic board subdev registration function Laurent Pinchart
2011-05-19 18:34 ` [RFC/PATCH 2/2] omap3isp: Use generic " Laurent Pinchart
2011-05-20 7:14 ` [RFC/PATCH 1/2] v4l: Add generic board " Sylwester Nawrocki
2011-05-20 7:29 ` Laurent Pinchart
2011-05-20 7:52 ` Michael Jones [this message]
2011-05-20 8:53 ` Hans Verkuil
2011-05-20 9:05 ` Laurent Pinchart
2011-05-20 9:19 ` Hans Verkuil
2011-05-20 9:37 ` Laurent Pinchart
2011-05-20 9:52 ` Hans Verkuil
2011-05-20 10:12 ` Laurent Pinchart
2011-05-20 11:14 ` Hans Verkuil
2011-05-24 12:41 ` Laurent Pinchart
2011-05-20 10:36 ` Sylwester Nawrocki
2011-05-20 13:08 ` Guennadi Liakhovetski
2011-05-20 16:03 ` Laurent Pinchart
2011-11-07 22:35 Rick Bronson
2011-11-08 14:13 Rick Bronson
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