From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from lb1-smtp-cloud6.xs4all.net ([194.109.24.24]:60878 "EHLO lb1-smtp-cloud6.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752815AbbHaLlV (ORCPT ); Mon, 31 Aug 2015 07:41:21 -0400 Message-ID: <55E43D28.9050909@xs4all.nl> Date: Mon, 31 Aug 2015 13:40:24 +0200 From: Hans Verkuil MIME-Version: 1.0 To: Mauro Carvalho Chehab , Linux Media Mailing List CC: Mauro Carvalho Chehab Subject: Re: [PATCH v8 31/55] [media] media: add macros to check if subdev or V4L2 DMA References: <55E43B14.9050506@xs4all.nl> In-Reply-To: <55E43B14.9050506@xs4all.nl> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 08/31/2015 01:31 PM, Hans Verkuil wrote: > On 08/30/2015 05:06 AM, Mauro Carvalho Chehab wrote: >> As we'll be removing entity subtypes from the Kernel, we need >> to provide a way for drivers and core to check if a given >> entity is represented by a V4L2 subdev or if it is an V4L2 >> I/O entity (typically with DMA). > > This needs more discussion. The plan (as I understand it) is to have properties > that describe the entity's functionalities. > > The existing entity subtypes will exist only as backwards compat types, but in > the future properties should be used to describe the functionalities. > > This raises the question if we shouldn't use MEDIA_ENT_T_V4L2_SUBDEV to tell > userspace that this is a subdev-controlled entity, and let userspace look at > the properties to figure out what it is exactly? > > It could be that this is a transitional patch, and this will be fixed later. > If so, this should be mentioned in the commit message. FYI, I'm skipping patches that change the MEDIA_ENT_T_V4L2_SUBDEV usage until I understand the long-term plan for this define as discussed above. Regards, Hans