From patchwork Wed Feb 21 15:54:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Gaignard X-Patchwork-Id: 13565784 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3DE84C48BC3 for ; Wed, 21 Feb 2024 15:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=OheT8/tav1WV1wBmHuh8LTsA4aLTyEhHe1crpHzilDk=; b=tUOtGXmHyz6YIG zgYftvgMucspfpGk9zpc4S/gMwS4mLJxzdvz/hla6RxM0ddh2OB7rQscr0kc4Xe9Y7ARTnLezzJOx rDmuMgiF7pTeqK2mOjZ8Pt8nFhz6w+qLIYynRidPyuuPviu98GM34f6RsEMoP73/RoQXjFUcFVRKo Dtg8u6pjEtqFUfWwKxGebtgzse7jOGz3Nr0gAmFM7WxlFzFXlkIRPPksAwgiggoN5l3WD4nNBJPkJ DmVM+VgAYTsLajp/rPiduxQQNMZ6txYIn2DT3sYcuWHWAPP3gYXXNFsJXg8zqiw47GsD3NshLQtTp s3gyRALiLu95dvZj+Ihg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rcovz-00000001aHq-1lvc; Wed, 21 Feb 2024 15:54:59 +0000 Received: from madrid.collaboradmins.com ([2a00:1098:ed:100::25]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rcovl-00000001a7d-2Tuv for linux-rockchip@lists.infradead.org; Wed, 21 Feb 2024 15:54:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1708530883; bh=AV/2+6DOS7yOUx5UFiYF0NGULQdHl7NCcDnBNq974F0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bAgbh62sJ9Y9UY8RBnu7iHcby2xc0DCVSiF5aijFb8TDGa7xzGSo+K+AmPjw76ATh ouuSxDS+/9zMWWSTxV2N6VHHlloLQEbTrcxfr44i9ME4yteMHPSqIkg75Nq4FThKeD yVQgbDiVpBDjOzHDGqvdFvn5FVYHqqF4MH9iNxkVEH608OxR30dZZvK23rFOONs746 kHl9qiu+tCwozggomY7xtmiXbYf7tZmgiqdzn+DjjjC6MqInAo0+DJ6KL6lN+1VAk8 fx3Dh9+wBv614X3aSGzHnAhKJeNOfgdOVlRofL/jDbXuA+oF4HyWx/K2y8QeD244VI gUyCWeRQa7GNA== Received: from benjamin-XPS-13-9310.. (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: benjamin.gaignard) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 00D3F3781116; Wed, 21 Feb 2024 15:54:42 +0000 (UTC) From: Benjamin Gaignard To: mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, hverkuil-cisco@xs4all.nl, nicolas@ndufresne.ca Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, kernel@collabora.com, Benjamin Gaignard Subject: [PATCH v20 2/9] videobuf2: Add min_reqbufs_allocation field to vb2_queue structure Date: Wed, 21 Feb 2024 16:54:28 +0100 Message-Id: <20240221155435.100093-3-benjamin.gaignard@collabora.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240221155435.100093-1-benjamin.gaignard@collabora.com> References: <20240221155435.100093-1-benjamin.gaignard@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240221_075445_852284_ED552695 X-CRM114-Status: GOOD ( 25.89 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org Add 'min_reqbufs_allocation' field in the vb2_queue structure so drivers can specify the minimum number of buffers to allocate when calling VIDIOC_REQBUFS. When initializing the queue, v4l2 core makes sure that the following constraints are respected: - the minimum number of buffers to allocate must be at least 2 because one buffer is used by the hardware while the other is being processed by userspace. -if the driver needs 'min_queued_buffers' in the queue before calling start_streaming(), then the minimum requirement is 'min_queued_buffers + 1' to keep at least one buffer available for userspace. Simplify __vb2_init_fileio() by using 'min_reqbufs_allocation' directly to avoid duplicating the minimum number of buffers to allocate computation. Signed-off-by: Benjamin Gaignard --- .../media/common/videobuf2/videobuf2-core.c | 38 +++++++++++-------- include/media/videobuf2-core.h | 15 +++++++- 2 files changed, 37 insertions(+), 16 deletions(-) diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index d8b3c04cb3b5..58c495b253ce 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -866,7 +866,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, /* * Make sure the requested values and current defaults are sane. */ - num_buffers = max_t(unsigned int, *count, q->min_queued_buffers); + num_buffers = max_t(unsigned int, *count, q->min_reqbufs_allocation); num_buffers = min_t(unsigned int, num_buffers, q->max_num_buffers); memset(q->alloc_devs, 0, sizeof(q->alloc_devs)); /* @@ -918,7 +918,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, * There is no point in continuing if we can't allocate the minimum * number of buffers needed by this vb2_queue. */ - if (allocated_buffers < q->min_queued_buffers) + if (allocated_buffers < q->min_reqbufs_allocation) ret = -ENOMEM; /* @@ -2524,6 +2524,25 @@ int vb2_core_queue_init(struct vb2_queue *q) if (WARN_ON(q->supports_requests && q->min_queued_buffers)) return -EINVAL; + /* + * The minimum requirement is 2: one buffer is used + * by the hardware while the other is being processed by userspace. + */ + if (q->min_reqbufs_allocation < 2) + q->min_reqbufs_allocation = 2; + + /* + * If the driver needs 'min_queued_buffers' in the queue before + * calling start_streaming() then the minimum requirement is + * 'min_queued_buffers + 1' to keep at least one buffer available + * for userspace. + */ + if (q->min_reqbufs_allocation < q->min_queued_buffers + 1) + q->min_reqbufs_allocation = q->min_queued_buffers + 1; + + if (WARN_ON(q->min_reqbufs_allocation > q->max_num_buffers)) + return -EINVAL; + INIT_LIST_HEAD(&q->queued_list); INIT_LIST_HEAD(&q->done_list); spin_lock_init(&q->done_lock); @@ -2717,7 +2736,6 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read) struct vb2_fileio_data *fileio; struct vb2_buffer *vb; int i, ret; - unsigned int count = 0; /* * Sanity check @@ -2738,18 +2756,8 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read) if (q->streaming || vb2_get_num_buffers(q) > 0) return -EBUSY; - /* - * Start with q->min_queued_buffers + 1, driver can increase it in - * queue_setup() - * - * 'min_queued_buffers' buffers need to be queued up before you - * can start streaming, plus 1 for userspace (or in this case, - * kernelspace) processing. - */ - count = max(2, q->min_queued_buffers + 1); - dprintk(q, 3, "setting up file io: mode %s, count %d, read_once %d, write_immediately %d\n", - (read) ? "read" : "write", count, q->fileio_read_once, + (read) ? "read" : "write", q->min_reqbufs_allocation, q->fileio_read_once, q->fileio_write_immediately); fileio = kzalloc(sizeof(*fileio), GFP_KERNEL); @@ -2763,7 +2771,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read) * Request buffers and use MMAP type to force driver * to allocate buffers by itself. */ - fileio->count = count; + fileio->count = q->min_reqbufs_allocation; fileio->memory = VB2_MEMORY_MMAP; fileio->type = q->type; q->fileio = fileio; diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 6ad36da91f8d..2ca120f18edf 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -550,9 +550,21 @@ struct vb2_buf_ops { * @start_streaming can be called. Used when a DMA engine * cannot be started unless at least this number of buffers * have been queued into the driver. - * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + * VIDIOC_REQBUFS will ensure at least @min_queued_buffers + 1 * buffers will be allocated. Note that VIDIOC_CREATE_BUFS will not * modify the requested buffer count. + * @min_reqbufs_allocation: the minimum number of buffers to be allocated when + * calling VIDIOC_REQBUFS. Note that VIDIOC_CREATE_BUFS will *not* + * modify the requested buffer count and does not use this field. + * Drivers can set this if there has to be a certain number of + * buffers available for the hardware to work effectively. + * This allows calling VIDIOC_REQBUFS with a buffer count of 1 and + * it will be automatically adjusted to a workable buffer count. + * If set, then @min_reqbufs_allocation must be larger than + * @min_queued_buffers + 1. + * If this field is > 3, then it is highly recommended that the + * driver implements the V4L2_CID_MIN_BUFFERS_FOR_CAPTURE/OUTPUT + * control. */ /* * Private elements (won't appear at the uAPI book): @@ -619,6 +631,7 @@ struct vb2_queue { u32 timestamp_flags; gfp_t gfp_flags; u32 min_queued_buffers; + u32 min_reqbufs_allocation; struct device *alloc_devs[VB2_MAX_PLANES];