From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from sbevan.dsl.xmission.com ([166.70.26.173]:33328 "EHLO nebo.bevan.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754721AbZEZT6y (ORCPT ); Tue, 26 May 2009 15:58:54 -0400 Received: from [192.168.0.4] (scottfam.dsl.xmission.com [166.70.240.45]) by nebo.bevan.us (Postfix) with ESMTP id C9BA6486E23 for ; Tue, 26 May 2009 13:51:14 -0600 (MDT) Subject: RFC - Locking resources between V4L and DVB interfaces From: Rusty Scott To: linux-media@vger.kernel.org Content-Type: text/plain Date: Tue, 26 May 2009 13:51:15 -0600 Message-Id: <1243367475.15846.19.camel@godzilla> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hello all, I talked to Mauro offline about this issue and he indicated that it was an area that could use some attention. So I have decided to take this issue on and am looking for comments about how this should work. Issue: The DVB and V4L interfaces are considered different devices from a system standpoint. However they often share a hardware resource, such as a tuner, on many cards. There is currently no locking on the shared resource, so one interface could interfere with the resources already in use by the other. My experience in the code tree and API are not very in depth. I've only helped maintain some card specific code to this point. I'm looking for comments and information on various ways to accomplish this and possible gotchas to watch out for. Any pointers, suggestions or other help on this would be appreciated. Thanks, Rusty