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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 96408C47254 for ; Thu, 30 Apr 2020 20:10:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74BE720774 for ; Thu, 30 Apr 2020 20:10:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="HyHQiCKc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbgD3UKJ (ORCPT ); Thu, 30 Apr 2020 16:10:09 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:14149 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726338AbgD3UKJ (ORCPT ); Thu, 30 Apr 2020 16:10:09 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 30 Apr 2020 13:08:04 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 30 Apr 2020 13:10:08 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 30 Apr 2020 13:10:08 -0700 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 30 Apr 2020 20:10:08 +0000 Received: from [10.2.165.152] (10.124.1.5) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 30 Apr 2020 20:10:07 +0000 Subject: Re: [RFC PATCH v11 6/9] media: tegra: Add Tegra210 Video input driver To: Dmitry Osipenko , , , , , , CC: , , , , , References: <1588197606-32124-1-git-send-email-skomatineni@nvidia.com> <1588197606-32124-7-git-send-email-skomatineni@nvidia.com> From: Sowjanya Komatineni Message-ID: Date: Thu, 30 Apr 2020 13:08:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To DRHQMAIL107.nvidia.com (10.27.9.16) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1588277285; bh=bU+Gy6O+uYdQwdtawNbqdmqoPb5HNcT3EKUwg12HVTg=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=HyHQiCKccOmKDCyjff09+lV+ozUKZQWBN6MvpgIuXiK3zzsPD+iaHW31AJVM9WEf8 3MhEAYDuFgWjAmTiA2nyp5hm2cWXDXRr9huwo4ka9jmDEav+j+9KjV1OrWK9rMtHxf E13nWbrEMddT8yfbF1Zr+3D7YdUemyLDzPNp2b4282gI3lKPWS5GuoLeJX2RnhV5/H IYXVJakraLOdk5gznQvw3PPuV5QkXip+u7ASm/aNrOIijgkG1NIZfujf5QR4dZxlBX zYBFFYvAZNw0VBi/9VeVTx+5vkDlhVSRa1WiX549lhJhvQ9RL/SVRQhMFsg4yWqdPy AKedr1Sv/TXKA== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/30/20 1:06 PM, Dmitry Osipenko wrote: > 30.04.2020 01:00, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> +static int chan_capture_kthread_start(void *data) >> +{ >> + struct tegra_vi_channel *chan =3D data; >> + struct tegra_channel_buffer *buf; >> + int err =3D 0; >> + >> + set_freezable(); >> + >> + while (1) { >> + try_to_freeze(); >> + >> + /* >> + * Source is not streaming if error is non-zero. >> + * So, do not dequeue buffers on error and let the thread sleep >> + * till kthread stop signal is received. >> + */ >> + wait_event_interruptible(chan->start_wait, >> + kthread_should_stop() || >> + (!list_empty(&chan->capture) && >> + !err)); > ... >> +static void tegra_channel_buffer_queue(struct vb2_buffer *vb) >> +{ >> + struct tegra_vi_channel *chan =3D vb2_get_drv_priv(vb->vb2_queue); >> + struct vb2_v4l2_buffer *vbuf =3D to_vb2_v4l2_buffer(vb); >> + struct tegra_channel_buffer *buf =3D to_tegra_channel_buffer(vbuf); >> + >> + /* put buffer into the capture queue */ >> + spin_lock(&chan->start_lock); >> + list_add_tail(&buf->queue, &chan->capture); >> + spin_unlock(&chan->start_lock); >> + >> + /* wait up kthread for capture */ >> + wake_up_interruptible(&chan->start_wait); >> +} > The V4L doc says that buffers could be enqueued before streaming is > started. I guess it should be a trouble here, shouldn't it? > > https://elixir.bootlin.com/linux/v5.7-rc3/source/include/media/videobuf2-= core.h#L379 what trouble are you referring here? I dont think so as we set min buffers needed as 2 always there will be 2=20 per-queued buffers. But buffers from this queue will be dequeued only when ready to=20 processes in the capture thread