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=-6.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED 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 20D4FC43387 for ; Tue, 8 Jan 2019 21:28:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4B0520883 for ; Tue, 8 Jan 2019 21:28:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="uOfBo26D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730159AbfAHV2L (ORCPT ); Tue, 8 Jan 2019 16:28:11 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:39028 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729511AbfAHV2L (ORCPT ); Tue, 8 Jan 2019 16:28:11 -0500 Received: from avalon.localnet (dfj612ybrt5fhg77mgycy-3.rev.dnainternet.fi [IPv6:2001:14ba:21f5:5b00:2e86:4862:ef6a:2804]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 74A19586; Tue, 8 Jan 2019 22:28:08 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1546982888; bh=AKQITtpu4zuSO93qTr4/BO567gEQeeCLPJfMSQEe4OA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uOfBo26DP8b3PeYswSbbdNLW2kPGjj9mP8wmDNEz5Sl2ikYhiSNJYvEdhEzBg9smf +X5PUUTioYR+5PG1C3Z0fs1mHINHETuDhpJM4A+ToeexpxfjGWc2V0AgHG3AQbrdg2 EpXULP79Fqjwrf2AUg/67cjm6hjZLKTAnAEGEwyE= From: Laurent Pinchart To: Mauro Carvalho Chehab Cc: Mikhail Gavrilov , linux-media@vger.kernel.org Subject: Re: Kernel error "Unknown pixelformat 0x00000000" occurs when I start capture video Date: Tue, 08 Jan 2019 23:29:17 +0200 Message-ID: <2295088.CIBgFgJDf4@avalon> Organization: Ideas on Board Oy In-Reply-To: <20190108164916.55aa9b93@coco.lan> References: <20190108164916.55aa9b93@coco.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Mauro, On Tuesday, 8 January 2019 20:49:16 EET 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. Thank you for the detailed and clear explanation. > 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/pi > xfmt-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. > > 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. -- Regards, Laurent Pinchart