From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Cc: Alan <alan@linux.intel.com>,
vincent.hervieux@gmail.com, sakari.ailus@linux.intel.com,
linux-media@vger.kernel.org
Subject: Re: [PATCH 1/3] atomisp: Fix up the open v load race
Date: Tue, 12 Dec 2017 15:55:25 +0000 [thread overview]
Message-ID: <20171212155525.7ab67f2a@alans-desktop> (raw)
In-Reply-To: <20171212090350.0b57dbbb@vento.lan>
On Tue, 12 Dec 2017 09:03:50 -0200
Mauro Carvalho Chehab <mchehab@s-opensource.com> wrote:
> Em Mon, 06 Nov 2017 23:36:36 +0000
> Alan <alan@linux.intel.com> escreveu:
>
> > This isn't the ideal final solution but it stops the main problem for now
> > where an open (often from udev) races the device initialization and we try
> > and load the firmware twice at the same time. This needless to say doesn't
> > usually end well.
>
> What we do on most drivers is that video_register_device() is called
> only after all hardware init.
>
> That's usually enough to avoid race conditions with udev, although
> a mutex is also common in order to avoid some other race conditions
> between open/close - with can happen with multiple opens.
There are a whole bunch of other ordering issues to deal with in the
atomisp case beyond this - another one is that the camera probe can race
the ISP probe.
Quite a lot of the registration code needs fixing, but I'm prioritizing
stabilizing the code first, and trying to get the Cherrytrail version
going.
Alan
prev parent reply other threads:[~2017-12-12 15:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-06 23:36 [PATCH 1/3] atomisp: Fix up the open v load race Alan
2017-11-06 23:36 ` [PATCH 2/3] atomisp: fix vfree of bogus data on unload Alan
2017-11-13 22:05 ` Sakari Ailus
2017-11-14 0:16 ` Alan Cox
2017-11-14 14:10 ` Sakari Ailus
2017-11-06 23:37 ` [PATCH 3/3] atomisp: hmm gives a bogus warning " Alan
2017-12-12 11:03 ` [PATCH 1/3] atomisp: Fix up the open v load race Mauro Carvalho Chehab
2017-12-12 15:55 ` Alan Cox [this message]
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