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 F2973C4332F for ; Tue, 15 Feb 2022 11:01:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236859AbiBOLB2 (ORCPT ); Tue, 15 Feb 2022 06:01:28 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:37740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236830AbiBOLBZ (ORCPT ); Tue, 15 Feb 2022 06:01:25 -0500 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 82654F956C; Tue, 15 Feb 2022 03:01:15 -0800 (PST) Received: from benjamin-XPS-13-9310.. (unknown [IPv6:2a01:e0a:120:3210:6d7b:ae43:289b:7e7c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: benjamin.gaignard) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id D2AEA1F444D0; Tue, 15 Feb 2022 11:01:12 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1644922873; bh=j2A4NMSFKaArnsLVO73dDEOpv7p5lUGniQuI/KRT0iU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MIWd6bRq5QrtPVR9A0Zxw1KYRLSgRl9262dVOZdU3VNsOOY+nq4dMzxoeT2Sw7d4d Kn/WKgMc9OL4o3RmJTqNlXqn2TufiLROIKh9xkkjNq2oqu5RJBCOoZAesMUG0G7EXM 8NuyZFj19Z+Qb9LNWEH37LE2w9/aBk/WKDtVOmD4Dde0SOhGfi//nyQLMEUP4yuGt/ mW34vWyP7aO8ZhttR1YNZvpbTqtkXABw769Izo2PYeobAi+Pmd8SWXsKDgDu6bveTu JARwO8EFy4F1Ipwz9SksZtq8FjcKtP6dQvMnU8+OJTo5JfKIk8q0WL57dsjrcNmt6w No4D6omyiHWIQ== From: Benjamin Gaignard To: mchehab@kernel.org, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, gregkh@linuxfoundation.org, mripard@kernel.org, paul.kocialkowski@bootlin.com, wens@csie.org, jernej.skrabec@gmail.com, hverkuil-cisco@xs4all.nl, jonas@kwiboo.se, nicolas@ndufresne.ca Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, kernel@collabora.com, knaerzche@gmail.com, jc@kynesim.co.uk Subject: [RFC v2 1/8] videodev2.h: add V4L2_CTRL_FLAG_DYNAMIC_ARRAY Date: Tue, 15 Feb 2022 12:00:56 +0100 Message-Id: <20220215110103.241297-2-benjamin.gaignard@collabora.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220215110103.241297-1-benjamin.gaignard@collabora.com> References: <20220215110103.241297-1-benjamin.gaignard@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hans Verkuil Add a new flag that indicates that this control is a dynamically sized array. Also document this flag. Currently dynamically sized arrays are limited to one dimensional arrays, but that might change in the future if there is a need for it. The initial use-case of dynamic arrays are stateless codecs. A frame can be divided in many slices, so you want to provide an array containing slice information for each slice. Typically the number of slices is small, but the standard allow for hundreds or thousands of slices. Dynamic arrays are a good solution since sizing the array for the worst case would waste substantial amounts of memory. Signed-off-by: Hans Verkuil --- .../userspace-api/media/v4l/vidioc-queryctrl.rst | 8 ++++++++ include/uapi/linux/videodev2.h | 1 + 2 files changed, 9 insertions(+) diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst index 88f630252d98..a20dfa2a933b 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst @@ -625,6 +625,14 @@ See also the examples in :ref:`control`. ``V4L2_CTRL_FLAG_GRABBED`` flag when buffers are allocated or streaming is in progress since most drivers do not support changing the format in that case. + * - ``V4L2_CTRL_FLAG_DYNAMIC_ARRAY`` + - 0x0800 + - This control is a dynamically sized 1-dimensional array. It + behaves the same as a regular array, except that the number + of elements as reported by the ``elems`` field is between 1 and + ``dims[0]``. So setting the control with a differently sized + array will change the ``elems`` field when the control is + queried afterwards. Return Value ============ diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index df8b9c486ba1..e27c8eae78c9 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -1884,6 +1884,7 @@ struct v4l2_querymenu { #define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x0100 #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x0200 #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400 +#define V4L2_CTRL_FLAG_DYNAMIC_ARRAY 0x0800 /* Query flags, to be ORed with the control ID */ #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000 -- 2.32.0