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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=unavailable 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 AEA1BC43460 for ; Fri, 2 Apr 2021 12:27:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8556461158 for ; Fri, 2 Apr 2021 12:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235416AbhDBM1p (ORCPT ); Fri, 2 Apr 2021 08:27:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235373AbhDBM1n (ORCPT ); Fri, 2 Apr 2021 08:27:43 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94B49C0613E6; Fri, 2 Apr 2021 05:27:41 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id 5C3AE1F442CC Message-ID: <5674859659f93ba547cad43528ac94ef145347b3.camel@collabora.com> Subject: Re: [PATCH v8 09/13] media: uapi: Add a control for HANTRO driver From: Ezequiel Garcia To: Benjamin Gaignard , p.zabel@pengutronix.de, mchehab@kernel.org, robh+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, festevam@gmail.com, lee.jones@linaro.org, gregkh@linuxfoundation.org, mripard@kernel.org, paul.kocialkowski@bootlin.com, wens@csie.org, jernej.skrabec@siol.net, hverkuil-cisco@xs4all.nl, emil.l.velikov@gmail.com Cc: kernel@pengutronix.de, linux-imx@nxp.com, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, kernel@collabora.com Date: Fri, 02 Apr 2021 09:27:28 -0300 In-Reply-To: <20210401160003.88803-10-benjamin.gaignard@collabora.com> References: <20210401160003.88803-1-benjamin.gaignard@collabora.com> <20210401160003.88803-10-benjamin.gaignard@collabora.com> Organization: Collabora Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.2-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Benjamin, Thanks for the patch. On Thu, 2021-04-01 at 17:59 +0200, Benjamin Gaignard wrote: > The HEVC HANTRO driver needs to know the number of bits to skip at > the beginning of the slice header. > That is a hardware specific requirement so create a dedicated control > that this purpose. > > Signed-off-by: Benjamin Gaignard > --- > version 5: >  - Be even more verbose in control documentation. >  - Do not create class for the control. > version 4: > - The control is now an integer which is enough to provide the numbers >   of bits to skip. > version 3: > - Fix typo in field name > >  .../userspace-api/media/drivers/hantro.rst         | 14 ++++++++++++++ >  .../userspace-api/media/drivers/index.rst          |  1 + >  include/uapi/linux/v4l2-controls.h                 | 13 +++++++++++++ >  3 files changed, 28 insertions(+) >  create mode 100644 Documentation/userspace-api/media/drivers/hantro.rst > > diff --git a/Documentation/userspace-api/media/drivers/hantro.rst b/Documentation/userspace-api/media/drivers/hantro.rst > new file mode 100644 > index 000000000000..78dcd2a44a03 > --- /dev/null > +++ b/Documentation/userspace-api/media/drivers/hantro.rst > @@ -0,0 +1,14 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +Hantro video decoder driver > +=========================== > + > +The Hantro video decoder driver implements the following driver-specific controls: > + > +``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)`` > +    Specifies to Hantro HEVC video decoder driver the number of data (in bits) to > +    skip in the slice segment header. > +    If non-IDR, the bits to be skipped go from syntax element "pic_output_flag" > +    to before syntax element "slice_temporal_mvp_enabled_flag". > +    If IDR, the skipped bits are just "pic_output_flag" > +    (separate_colour_plane_flag is not supported). > diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst > index 1a9038f5f9fa..12e3c512d718 100644 > --- a/Documentation/userspace-api/media/drivers/index.rst > +++ b/Documentation/userspace-api/media/drivers/index.rst > @@ -33,6 +33,7 @@ For more details see the file COPYING in the source distribution of Linux. >   >         ccs >         cx2341x-uapi > +        hantro >         imx-uapi >         max2175 >         meye-uapi > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h > index f3376aafea65..1dfb874b6272 100644 > --- a/include/uapi/linux/v4l2-controls.h > +++ b/include/uapi/linux/v4l2-controls.h > @@ -869,6 +869,19 @@ enum v4l2_mpeg_mfc51_video_force_frame_type { >  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC              (V4L2_CID_CODEC_MFC51_BASE+53) >  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P               (V4L2_CID_CODEC_MFC51_BASE+54) >   > +/*  MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */ We are moving away from "MPEG" terminology for codecs. > +#define V4L2_CID_CODEC_HANTRO_BASE                             (V4L2_CTRL_CLASS_CODEC | 0x1200) Using V4L2_CTRL_CLASS_CODEC_STATELESS is IMO better, since this belongs to a stateless decoder. And also, since we are still a bit unsure about the syntax of this parameter (given it's not documented): how about keeping the V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP definition in drivers/staging/media/hantro/hantro.h ? This would be a hint for applications that this control is a quirk. Hans, Philipp, any thoughts on this? Regards, Ezequiel