linux-kernel - Re: [PATCH] eeepc-laptop: enable camera by default

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Message-ID: <20090607232856.GA1805@srcf.ucam.org>
Date:	Mon, 8 Jun 2009 00:28:58 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	alan-jenkins@...fmail.co.uk
Cc:	Pekka Enberg <penberg@...helsinki.fi>,
	Corentin Chary <corentin.chary@...il.com>,
	acpi4asus-user@...ts.sourceforge.net, len.brown@...el.com,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	Darren Salt <linux@...mustbejoking.demon.co.uk>
Subject: Re: [PATCH] eeepc-laptop: enable camera by default

On Sun, Jun 07, 2009 at 04:41:30PM +0100, Alan Jenkins wrote:

> Hmm, some cameras have input devices (i.e. buttons). In fact, uvcvideo
> registers an input device on my EEE even though it has no buttons.  I
> think that needs investigating :-(.
> 
> It's quite likely that the buttons can stop working when suspended.
> And there might be other devices with the same IDs, which have a
> button wired up.

A change has recently been committed that results in the button only 
working if the v4l device is open. Otherwise you've got several wakeups 
a second due to the polling of the button endpoint. I'm assuming that 
opening the device disables autosuspend, so I wouldn't worry about that.

It'd be interesting to try enabling autosuspend on all UVC devices. Can 
a driver indicate that its hardware supports it?
-- 
Matthew Garrett | mjg59@...f.ucam.org
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