From patchwork Wed Mar 11 17:42:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ezequiel Garcia X-Patchwork-Id: 11432417 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D177E14E5 for ; Wed, 11 Mar 2020 17:47:21 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 7072220734 for ; Wed, 11 Mar 2020 17:47:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pHDQScBC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7072220734 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JeBLQGzBFswGQMq6oCOb0YUB4+jQ//2TDcbdlh8vpOY=; b=pHDQScBCGycROS duJg5ZrS3DtomgS2fgEFYz2t4OFTd2ryCfwm9hUAOx5vsc2ZNIAzSUYKtR/W0FtUZtaI7+6R+jZsu afNkHKQZ/iKZ2Oq1joSaUFnJk2yrhg0vcz8wLxnwfSDW/2qnJHUz7XZEuOTOPljJ6US4H2Y3+sfrw 78DFAyyCsAxfRaP6t81CZDt6V7/pW9tv3bHqnM+4CUAqUToT5i5x2Xfh/B6ms5Wgi8v1UPOKzpF57 wS1bGH84B9VNOHVdh/6wFPQfVZt9tC3eZO6TVBNxHG74oz3VE6EvV4VD8/ID2ufIP4m86dXCJeDtq vPEdXQ93j+hTJjNAfAfw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jC5Rt-0001aD-L7; Wed, 11 Mar 2020 17:47:17 +0000 Received: from bhuna.collabora.co.uk ([46.235.227.227]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jC5Rq-0001Xd-Og for linux-rockchip@lists.infradead.org; Wed, 11 Mar 2020 17:47:16 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id 639D72912DD From: Ezequiel Garcia To: linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/6] v4l2-mem2mem: return CAPTURE buffer first Date: Wed, 11 Mar 2020 14:42:55 -0300 Message-Id: <20200311174300.19407-2-ezequiel@collabora.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200311174300.19407-1-ezequiel@collabora.com> References: <20200311174300.19407-1-ezequiel@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200311_104714_931995_00D30391 X-CRM114-Status: UNSURE ( 8.66 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.0 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [46.235.227.227 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tomasz Figa , Heiko Stuebner , Alexandre Courbot , Jonas Karlman , Nicolas Dufresne , Hans Verkuil , Jeffrey Kardatzke , kernel@collabora.com, Ezequiel Garcia Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org When the request API is used, typically an OUTPUT (src) buffer will be part of a request. A userspace process will be typically blocked, waiting on the request file descriptor. Returning the OUTPUT (src) buffer will wake-up such processes, who will immediately attempt to dequeue the CAPTURE buffer, only to find it's still unavailable. Therefore, change v4l2_m2m_buf_done_and_job_finish returning the CAPTURE (dst) buffer first, to avoid signalling the request file descriptor prematurely, i.e. before the CAPTURE buffer is done. When the request API is not used, this change should have no impact. Signed-off-by: Ezequiel Garcia Tested-by: Nicolas Dufresne --- drivers/media/v4l2-core/v4l2-mem2mem.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c index 8986c31176e9..62ac9424c92a 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -504,12 +504,21 @@ void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev, if (WARN_ON(!src_buf || !dst_buf)) goto unlock; - v4l2_m2m_buf_done(src_buf, state); dst_buf->is_held = src_buf->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF; if (!dst_buf->is_held) { v4l2_m2m_dst_buf_remove(m2m_ctx); v4l2_m2m_buf_done(dst_buf, state); } + /* + * If the request API is being used, returning the OUTPUT + * (src) buffer will wake-up any process waiting on the + * request file descriptor. + * + * Therefore, return the CAPTURE (dst) buffer first, + * to avoid signalling the request file descriptor + * before the CAPTURE buffer is done. + */ + v4l2_m2m_buf_done(src_buf, state); schedule_next = _v4l2_m2m_job_finish(m2m_dev, m2m_ctx); unlock: spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);