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 67449C433EF for ; Wed, 22 Dec 2021 06:10:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239218AbhLVGKl (ORCPT ); Wed, 22 Dec 2021 01:10:41 -0500 Received: from twspam01.aspeedtech.com ([211.20.114.71]:55989 "EHLO twspam01.aspeedtech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229955AbhLVGKj (ORCPT ); Wed, 22 Dec 2021 01:10:39 -0500 Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 1BM65Bfb064928; Wed, 22 Dec 2021 14:05:11 +0800 (GMT-8) (envelope-from jammy_huang@aspeedtech.com) Received: from [192.168.2.115] (192.168.2.115) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 22 Dec 2021 14:10:37 +0800 Message-ID: Date: Wed, 22 Dec 2021 14:10:37 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH 4/4] media: aspeed: Fix timing polarity incorrect Content-Language: en-US To: Joel Stanley CC: Eddie James , Mauro Carvalho Chehab , Andrew Jeffery , "linux-media@vger.kernel.org" , OpenBMC Maillist , Linux ARM , linux-aspeed , Linux Kernel Mailing List References: <20211217095403.2618-1-jammy_huang@aspeedtech.com> <20211217095403.2618-5-jammy_huang@aspeedtech.com> From: Jammy Huang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [192.168.2.115] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 1BM65Bfb064928 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joel, OK, I will update in next patch as you advised. Thanks for your review. On 2021/12/22 上午 09:22, Joel Stanley wrote: > On Fri, 17 Dec 2021 at 09:54, Jammy Huang wrote: >> This is a workaround for polarity unstable. >> Sync value get by VR09C counts from sync's rising edge, which means >> sync's polarity is negative if sync value is bigger than total/2. >> >> Signed-off-by: Jammy Huang >> --- >> drivers/media/platform/aspeed-video.c | 18 ++++++++++++++++++ >> 1 file changed, 18 insertions(+) >> >> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c >> index 5ad3a20c5bac..f628f69bb7dd 100644 >> --- a/drivers/media/platform/aspeed-video.c >> +++ b/drivers/media/platform/aspeed-video.c >> @@ -989,6 +989,15 @@ static void aspeed_video_get_resolution(struct aspeed_video *video) >> video->frame_top = FIELD_GET(VE_SRC_TB_EDGE_DET_TOP, >> src_tb_edge); >> det->vsync = FIELD_GET(VE_SYNC_STATUS_VSYNC, sync); >> + /* >> + * Workaround for polarity detection >> + * Use sync(VR098) counts from sync's rising edge till falling >> + * edge to tell sync polarity. >> + */ >> + if (det->vsync > (FIELD_GET(VE_MODE_DETECT_V_LINES, mds) >> 1)) > Are you right shifting as this is the value / 2? I think it's clearer > to write / 2 instead of >> 1. > > Mention in the comment that this is a workaround for when the sync > value is larger than half. > >> + det->polarities &= ~V4L2_DV_VSYNC_POS_POL; >> + else >> + det->polarities |= V4L2_DV_VSYNC_POS_POL; >> if (det->polarities & V4L2_DV_VSYNC_POS_POL) { >> det->vbackporch = video->frame_top - det->vsync; >> det->vfrontporch = >> @@ -1010,6 +1019,15 @@ static void aspeed_video_get_resolution(struct aspeed_video *video) >> video->frame_left = FIELD_GET(VE_SRC_LR_EDGE_DET_LEFT, >> src_lr_edge); >> det->hsync = FIELD_GET(VE_SYNC_STATUS_HSYNC, sync); >> + /* >> + * Workaround for polarity detection >> + * Use sync(VR098) counts from sync's rising edge till falling >> + * edge to tell sync polarity. >> + */ >> + if (det->hsync > (htotal >> 1)) >> + det->polarities &= ~V4L2_DV_HSYNC_POS_POL; >> + else >> + det->polarities |= V4L2_DV_HSYNC_POS_POL; >> if (det->polarities & V4L2_DV_HSYNC_POS_POL) { >> det->hbackporch = video->frame_left - det->hsync; >> det->hfrontporch = htotal - video->frame_right; >> -- >> 2.25.1 >> -- Best Regards Jammy