From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp1-g21.free.fr ([212.27.42.1]:44577 "EHLO smtp1-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754079Ab2EFSmi convert rfc822-to-8bit (ORCPT ); Sun, 6 May 2012 14:42:38 -0400 Date: Sun, 6 May 2012 20:43:47 +0200 From: Jean-Francois Moine To: Hans de Goede Cc: linux-media@vger.kernel.org Subject: Re: gspca zc3xx - JPEG quality / frame overflow Message-ID: <20120506204347.6d1a7af9@tele> In-Reply-To: <4FA6C024.9090408@redhat.com> References: <20120505205409.312e271f@tele> <4FA6C024.9090408@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: On Sun, 06 May 2012 20:17:08 +0200 Hans de Goede wrote: > > - as it is (read the register 11 every 100 ms), the work queue is > > usefull when there is no polling of the snapshot button, because the > > frame overflow is reported as the bit 0 in the forth byte (data[3]) > > of the interrupt messages. > > Interesting, so if the interrupt is enabled, then as soon as an overflow > happens, we get notified through the interrupt data? > > That may be an alternative to the worker thread, although the current > solution does work rather well, so I wonder if we should meddle with it. Hi Hans, Indeed, your solution works, but it does double polling, and the actual worker thread asks for a USB exchange each 100 ms. When using only the interrupt message, there is no overhead. Regards. -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/