From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sylwester Nawrocki Subject: Re: [PATCH 1/1] media: Entities with sink pads must have at least one enabled link Date: Wed, 14 Nov 2012 10:23:19 +0100 Message-ID: <50A36307.50502@samsung.com> References: <1351280777-4936-1-git-send-email-sakari.ailus@iki.fi> <20121113142409.GR25623@valkosipuli.retiisi.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20121113142409.GR25623@valkosipuli.retiisi.org.uk> Sender: linux-media-owner@vger.kernel.org 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 List-Id: alsa-devel@alsa-project.org 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