From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:46706 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932177Ab2KNJXX (ORCPT ); Wed, 14 Nov 2012 04:23:23 -0500 Received: from eusync1.samsung.com (mailout4.w1.samsung.com [210.118.77.14]) by mailout4.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MDH00D810RS1840@mailout4.w1.samsung.com> for linux-media@vger.kernel.org; Wed, 14 Nov 2012 09:23:52 +0000 (GMT) Received: from [106.116.147.32] by eusync1.samsung.com (Oracle Communications Messaging Server 7u4-23.01(7.0.4.23.0) 64bit (built Aug 10 2011)) with ESMTPA id <0MDH00C930QW6R90@eusync1.samsung.com> for linux-media@vger.kernel.org; Wed, 14 Nov 2012 09:23:21 +0000 (GMT) Message-id: <50A36307.50502@samsung.com> Date: Wed, 14 Nov 2012 10:23:19 +0100 From: Sylwester Nawrocki MIME-version: 1.0 To: Sakari Ailus Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, alsa-devel@alsa-project.org, laurent.pinchart@ideasonboard.com, broonie@opensource.wolfsonmicro.com, hverkuil@xs4all.nl Subject: Re: [PATCH 1/1] media: Entities with sink pads must have at least one enabled link References: <1351280777-4936-1-git-send-email-sakari.ailus@iki.fi> <20121113142409.GR25623@valkosipuli.retiisi.org.uk> In-reply-to: <20121113142409.GR25623@valkosipuli.retiisi.org.uk> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Sakari, On 11/13/2012 03:24 PM, Sakari Ailus wrote: > Hi all, > > Comments would be appreciated, either positive or negative. The omap3isp > driver does the same check itself currently, but I think this is more > generic than that. > > Thanks. > > On Fri, Oct 26, 2012 at 10:46:17PM +0300, Sakari Ailus wrote: >> If an entity has sink pads, at least one of them must be connected to >> another pad with an enabled link. If a driver with multiple sink pads has >> more strict requirements the check should be done in the driver itself. >> >> Just requiring one sink pad is connected with an enabled link is enough >> API-wise: entities with sink pads with only disabled links should not be >> allowed to stream in the first place, but also in a different operation mode >> a device might require only one of its pads connected with an active link. >> >> If an entity has an ability to function as a source entity another logical >> entity connected to the aforementioned one should be used for the purpose. Why not leave it to individual drivers ? I'm not sure if it is a good idea not to allow an entity with sink pads to be used as a source only. It might be appropriate for most of the cases but likely not all. I'm inclined not to add this requirement in the API. Just my opinion though. -- Thanks, Sylwester