From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BDE6C43387 for ; Wed, 9 Jan 2019 12:20:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3E9F20665 for ; Wed, 9 Jan 2019 12:20:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730566AbfAIMUU (ORCPT ); Wed, 9 Jan 2019 07:20:20 -0500 Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:47380 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727828AbfAIMUT (ORCPT ); Wed, 9 Jan 2019 07:20:19 -0500 Received: from valkosipuli.localdomain (valkosipuli.retiisi.org.uk [IPv6:2001:1bc8:1a6:d3d5::80:2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by hillosipuli.retiisi.org.uk (Postfix) with ESMTPS id 10FAE634C7F; Wed, 9 Jan 2019 14:19:01 +0200 (EET) Received: from sailus by valkosipuli.localdomain with local (Exim 4.89) (envelope-from ) id 1ghCp2-0002Z1-Ai; Wed, 09 Jan 2019 14:19:00 +0200 Date: Wed, 9 Jan 2019 14:19:00 +0200 From: Sakari Ailus To: Mauro Carvalho Chehab Cc: Mikhail Gavrilov , Laurent Pinchart , linux-media@vger.kernel.org Subject: Re: Kernel error "Unknown pixelformat 0x00000000" occurs when I start capture video Message-ID: <20190109121900.hbrpttmxz3gaotwx@valkosipuli.retiisi.org.uk> References: <386743082.UsI2JZZ8BA@avalon> <32231660.SI74LuYRbz@avalon> <20190108164916.55aa9b93@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190108164916.55aa9b93@coco.lan> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Jan 08, 2019 at 04:49:16PM -0200, Mauro Carvalho Chehab wrote: > Em Tue, 8 Jan 2019 21:11:41 +0500 > Mikhail Gavrilov escreveu: > > > On Tue, 8 Jan 2019 at 20:57, Laurent Pinchart > > wrote: > > > > > > Thank you. > > > > > > Your device exposes five formats: YUY2 (YUYV), YV12 (YVU420), NV12, P010 and > > > BGR3 (BGR24). They are all supported by V4L2 and the uvcvideo driver except > > > for the P010 format. This would be easy to fix in the uvcvideo driver if it > > > wasn't for the fact that the P010 format isn't support by V4L2. Adding support > > > for it isn't difficult, but I don't have time to do this myself at the moment. > > > Would you consider volunteering if I guide you ? :-) > > > > > > > Sure, I'd be happy to help. What is required of me? > > It shouldn't be hard. > > First, you need to add the new format at include/uapi/linux/videodev2.h, > like this one: > > #define V4L2_PIX_FMT_YUV420M v4l2_fourcc('Y', 'M', '1', '2') /* 12 YUV420 planar */ > > Please put it together with the other YUV formats. > > As the fourcc "P010" was not used on Linux yet, you could use it, > e. g., something like: > > #define V4L2_PIX_FMT_YUV_P10 v4l2_fourcc('P', '0', '1', '0') /* 10 YUV420 planar */ > > You need then to document it. Each V4L2 format should have a description, > like this: > > https://linuxtv.org/downloads/v4l-dvb-apis-new/uapi/v4l/pixfmt-yuv420m.html > > This is generated via a text file (using ReST syntax). On the above example, > it is produced by this file: > > https://git.linuxtv.org/media_tree.git/tree/Documentation/media/uapi/v4l/pixfmt-yuv420m.rst > > Writing it would take a little more time, but, provided that you don't > copy what's written from external docs, you could take a look at the > Internet for the P010 descriptions, and use the pixfmt-yuy420m.rst file > as the basis for a new pixfmt-p010.rst file. There is some work done on this but it's not finished; searching "P010" in Patchwork yields this: Just FYI. > > This will produce a patch similar to this one: > > https://git.linuxtv.org/media_tree.git/commit/?id=5df082e2312c > > Finally, you need to teach the uvc driver that it should report P010 > format, instead of 0x00000000, by adding it at uvc_format_desc uvc_fmts, > with the corresponding UVC GUID. We usually do this on a separate patch. > Something like this: > > https://git.linuxtv.org/media_tree.git/commit/?id=6ea0d588d35b > > Once you have the patches, submit it to the ML :-) > > You could take a look at the LinuxTV wiki page about how to submit, > at the developer's section: > > https://linuxtv.org/wiki/index.php/Developer_section > > In particular, take a look at "Submitting Your Work" section there. > > Thanks, > Mauro -- Sakari Ailus