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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3BBAC433EF for ; Fri, 26 Nov 2021 08:12:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359355AbhKZIPS (ORCPT ); Fri, 26 Nov 2021 03:15:18 -0500 Received: from twspam01.aspeedtech.com ([211.20.114.71]:65350 "EHLO twspam01.aspeedtech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243068AbhKZINS (ORCPT ); Fri, 26 Nov 2021 03:13:18 -0500 Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 1AQ7iYfs032630; Fri, 26 Nov 2021 15:44:34 +0800 (GMT-8) (envelope-from jammy_huang@aspeedtech.com) Received: from [192.168.2.115] (192.168.2.115) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 26 Nov 2021 16:08:49 +0800 Message-ID: Date: Fri, 26 Nov 2021 16:08:50 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v5 05/10] media: v4l: Add definition for the Aspeed JPEG format Content-Language: en-US To: Sakari Ailus CC: "eajames@linux.ibm.com" , "mchehab@kernel.org" , "joel@jms.id.au" , "andrew@aj.id.au" , "hverkuil-cisco@xs4all.nl" , "gregkh@linuxfoundation.org" , "laurent.pinchart@ideasonboard.com" , "linux-media@vger.kernel.org" , "openbmc@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-aspeed@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" References: <20211118074030.685-1-jammy_huang@aspeedtech.com> <20211118074030.685-6-jammy_huang@aspeedtech.com> <0bed6093-0af6-4fc4-716f-6cf8b1302320@aspeedtech.com> From: Jammy Huang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [192.168.2.115] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 1AQ7iYfs032630 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sakari, On 2021/11/23 下午 06:23, Sakari Ailus wrote: > Hi Jammy, > > On Fri, Nov 19, 2021 at 10:02:40AM +0800, Jammy Huang wrote: >> Hi Sakari, >> >> On 2021/11/18 下午 08:33, Sakari Ailus wrote: >>> Hi Jammy, >>> >>> On Thu, Nov 18, 2021 at 03:40:26PM +0800, Jammy Huang wrote: >>>> This introduces support for the Aspeed JPEG format, where the new frame >>>> can refer to previous frame to reduce the amount of compressed data. The >>>> concept is similar to I/P frame of video compression. I will compare the >>>> new frame with previous one to decide which macroblock's data is >>>> changed, and only the changed macroblocks will be compressed. >>>> >>>> This Aspeed JPEG format is used by the video engine on Aspeed platforms, >>>> which is generally adapted for remote KVM. >>>> >>>> Signed-off-by: Jammy Huang >>>> --- >>>> v5: >>>> - no update >>>> v4: >>>> - new >>>> --- >>>> Documentation/media/uapi/v4l/pixfmt-reserved.rst | 12 ++++++++++++ >>>> drivers/media/v4l2-core/v4l2-ioctl.c | 1 + >>>> include/uapi/linux/videodev2.h | 1 + >>>> 3 files changed, 14 insertions(+) >>>> >>>> diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst b/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> index b2cd155e691b..23c05063133d 100644 >>>> --- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> +++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> @@ -264,6 +264,18 @@ please make a proposal on the linux-media mailing list. >>>> of tiles, resulting in 32-aligned resolutions for the luminance plane >>>> and 16-aligned resolutions for the chrominance plane (with 2x2 >>>> subsampling). >>>> + * .. _V4L2-PIX-FMT-AJPG: >>>> + >>>> + - ``V4L2_PIX_FMT_AJPG`` >>>> + - 'AJPG' >>>> + - ASPEED JPEG format used by the aspeed-video driver on Aspeed platforms, >>>> + which is generally adapted for remote KVM. >>>> + On each frame compression, I will compare the new frame with previous >>>> + one to decide which macroblock's data is changed, and only the changed >>>> + macroblocks will be compressed. >>>> + >>>> + You could reference to chapter 36, Video Engine, of AST2600's datasheet >>>> + for more information. >>> Is this datasheet publicly available? Do you have a URL? >> Sorry, this datasheet is not publicly available. >> Hans mentioned this as well in the discussion below: >> >> https://lkml.org/lkml/2021/11/10/101 > If the vendor documentation is not publicly available, you'll need to have > the format documented here. Alternatively an open source implementation > (e.g. LGPL) is presumably fine, too. Please refer to https://github.com/AspeedTech-BMC/openbmc/releases/download/v07.02/SDK_User_Guide_v07.02.pdf. At Page 132, 'Video stream data format – ASPEED mode compression' describes the data format. Is above information  enough?? Besides, I have already had openbmc's kvm support this aspeed format. The source code of the implementation will be released after performance tuning finished. -- Best Regards Jammy