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From: Jean-Francois Moine <moinejf@free.fr>
To: Adam Baker <linux@baker-net.org.uk>
Cc: video4linux-list <video4linux-list@redhat.com>,
	sqcam-devel@lists.sourceforge.net,
	kilgota@banach.math.auburn.edu
Subject: Re: [REVIEW] Driver for SQ-905 based cameras
Date: Thu, 01 Jan 2009 18:38:18 +0100	[thread overview]
Message-ID: <1230831498.1702.40.camel@localhost> (raw)
In-Reply-To: <200901010033.58093.linux@baker-net.org.uk>

On Thu, 2009-01-01 at 00:33 +0000, Adam Baker wrote:
> Theodore Kilgore and I now have a driver for cameras based on the 
> SQ 905 chipset that is capable of producing images. It is based on gspca
	[snip]

Fine, but...

+ * This driver has used as a base the finepix driver and other gspca
+ * based drivers and may still contain code fragments taken from those
+ * drivers.

You did not look carefully at the finepix subdriver. Its webcams work
quite the same as yours, i.e. they ask for a control message to start
the bulk image transfer and an other control message to ack the
reception of the image. For that, the finepix implements a state machine
running at interrupt level or in the system work queue. All USB
exchanges are asynchronous, so that the system thread is not blocked.
Instead, you do a loop in this thread: then, this one cannot be used for
any other purpose!

I see only one alternative to do the image transfer:
- either implement a state machine as it is done in finepix,
- or have a specific work queue to handle the USB exchanges.

Best regards.

-- 
Ken ar c'hentañ |             ** Breizh ha Linux atav! **
Jef             |               http://moinejf.free.fr/


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  parent reply	other threads:[~2009-01-01 17:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-01  0:33 [REVIEW] Driver for SQ-905 based cameras Adam Baker
2009-01-01  6:11 ` Alexey Klimov
2009-01-01 12:28 ` Hans de Goede
2009-01-01 21:19   ` [sqcam-devel] " Adam Baker
     [not found]     ` <Pine.LNX.4.64.0901011539120.19217@banach.math.auburn.edu>
2009-01-02  7:55       ` Hans de Goede
2009-01-01 17:38 ` Jean-Francois Moine [this message]
     [not found]   ` <Pine.LNX.4.64.0901011220230.18838@banach.math.auburn.edu>
2009-01-01 20:48     ` Adam Baker

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