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,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 D0312C4724C for ; Thu, 30 Apr 2020 18:19:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A617B20836 for ; Thu, 30 Apr 2020 18:19:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="UIzTRbYX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726683AbgD3STi (ORCPT ); Thu, 30 Apr 2020 14:19:38 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:8280 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726336AbgD3STh (ORCPT ); Thu, 30 Apr 2020 14:19:37 -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 11:17:33 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 30 Apr 2020 11:19:37 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 30 Apr 2020 11:19:37 -0700 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 30 Apr 2020 18:19:37 +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 18:19:35 +0000 Subject: Re: [RFC PATCH v11 6/9] media: tegra: Add Tegra210 Video input driver From: Sowjanya Komatineni To: Dmitry Osipenko , , , , , , CC: , , , , , References: <1588197606-32124-1-git-send-email-skomatineni@nvidia.com> <1588197606-32124-7-git-send-email-skomatineni@nvidia.com> <4da289e6-036f-853b-beb4-379d6462adb0@gmail.com> <7d31d24f-f353-7e82-3ff9-cdba8b773d1e@nvidia.com> <06a4a067-8d54-4322-b2a6-14e82eaeda29@nvidia.com> Message-ID: <47873bbd-cf90-4595-5a99-7e9113327ecc@nvidia.com> Date: Thu, 30 Apr 2020 11:18:09 -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: <06a4a067-8d54-4322-b2a6-14e82eaeda29@nvidia.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) 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=1588270653; bh=ohRADXuDVSbfuKDemL6KlJp4gvc5xFXfIRWVd+qBixM=; h=X-PGP-Universal:Subject:From:To:CC:References:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=UIzTRbYXVHksNJe2IzQvFcLxdGJKeeB0UUtI8EJKq8drnM36u+15eSwIsxJcl1lXz 0z/kJj40OEH6AtwGMs3z48FH096qMn3++VHTU2md0zUDeCkPrjSp6p2OS3yrlzFUCt LNskQ6+n3BWKn5xCyKCBjTaHxNWG11GbhrkuaM9PqaGppirx6Lp4sdFwG40+5PHbDM Yii6YWdsF6vPA1L0Ijf3TgAoLElFjK65+lT7TPHEuNnqrKGN0TjTy6M6hu37FV+FDH jgE4fSIMEYLyRHosvo33XU/RNoZtu52+mqgTdteyTushcfupuK1Yl/I7euGQUkiWa7 UDifnOjDwwT6w== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/30/20 10:06 AM, Sowjanya Komatineni wrote: > > On 4/30/20 9:29 AM, Sowjanya Komatineni wrote: >> >> On 4/30/20 9:04 AM, Sowjanya Komatineni wrote: >>> >>> On 4/30/20 7:13 AM, Dmitry Osipenko wrote: >>>> 30.04.2020 17:02, Dmitry Osipenko =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>> 30.04.2020 16:56, Dmitry Osipenko =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>>> 30.04.2020 01:00, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82= : >>>>>>> +static int chan_capture_kthread_finish(void *data) >>>>>>> +{ >>>>>>> +=C2=A0=C2=A0=C2=A0 struct tegra_vi_channel *chan =3D data; >>>>>>> +=C2=A0=C2=A0=C2=A0 struct tegra_channel_buffer *buf; >>>>>>> + >>>>>>> +=C2=A0=C2=A0=C2=A0 set_freezable(); >>>>>>> + >>>>>>> +=C2=A0=C2=A0=C2=A0 while (1) { >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 try_to_freeze(); >>>>>> I guess it won't be great to freeze in the middle of a capture=20 >>>>>> process, so: >>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (list_empty(&chan->don= e)) >>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 t= ry_to_freeze(); >>>>> And here should be some locking protection in order not race with the >>>>> chan_capture_kthread_start because kthread_finish could freeze before >>>>> kthread_start. >>>> Or maybe both start / finish threads should simply be allowed to=20 >>>> freeze >>>> only when both capture and done lists are empty. >>>> >>>> if (list_empty(&chan->capture) && >>>> =C2=A0=C2=A0=C2=A0=C2=A0 list_empty(&chan->done)) >>>> =C2=A0=C2=A0=C2=A0=C2=A0try_to_freeze(); >>> >>> good to freeze when not in middle of the frame capture but why=20 >>> should we not allow freeze in between captures? >>> >>> Other drivers do allow freeze in between frame captures. >>> >>> I guess we can freeze before dequeue for capture and in finish=20 >>> thread we can freeze after capture done. This also don't need to=20 >>> check for list_empty with freeze to allow between frame captures. >>> >> Also if we add check for both lists empty, freeze is not allowed as=20 >> long as streaming is going on and in case of continuous streaming=20 >> freeze will never happen. > To allow freeze b/w frames (but not in middle of a frame), for capture_start thread, probably we can do unconditional try_to_freeze() for capture_finish thread, at end of capture done we can do=20 try_to_freeze() only when done list is empty > Hi Dmitry, > > Will update in v12 to not allow freeze in middle of a frame capture. > > Can you please confirm on above if you agree to allow freeze to happen=20 > in b/w frame captures? > > Also as most feedback has been received from you by now, appreciate if=20 > you can provide all in this v11 if you have anything else so we will=20 > not have any new changes after v12. > > Thanks > > Sowjanya >