From patchwork Wed Dec 25 02:34:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jun Chen X-Patchwork-Id: 11309935 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 7F90413A4 for ; Wed, 25 Dec 2019 02:37:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 549F12063A for ; Wed, 25 Dec 2019 02:37:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dnV1PVKt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726287AbfLYCgx (ORCPT ); Tue, 24 Dec 2019 21:36:53 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:34950 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726258AbfLYCgx (ORCPT ); Tue, 24 Dec 2019 21:36:53 -0500 Received: by mail-pj1-f66.google.com with SMTP id s7so1895352pjc.0; Tue, 24 Dec 2019 18:36:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=pdIbOs3lDS1y4SwDmDRq4hIBgk7hg9mVWHE7Ddel5uU=; b=dnV1PVKt2H+CsjlMYnYLbstb7q7F2tr2GthayCFodUykVCzuV3+rJuxSKxewzZDEfS +fpWJye1uNAyPx2619mh1RhTj+PIVRXpATrD6ootqBJ3hL5A3C6WL0EhUt1t5PcDOywV HODmZkrvchjgUdAE4tFFgH+HiIBY/B3FEbnxTEuN7OCyqEeu5pezOYwNqk9Wh5c2JM06 /hjjTtT7sWGxt/z+8jlxyGU3VMigiP1yePUyJPrjAFAddkl9LT/GeG0IkagmcuZJn6R2 Y95iL4CYmQ1Ny6chVsIntCfHRHuq52pWlF68tPPrUw/2x46pPhV0WYgAzM0dA6RZW8pF 04Pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=pdIbOs3lDS1y4SwDmDRq4hIBgk7hg9mVWHE7Ddel5uU=; b=qsC3ATkYvGLtO+KmYl0W/SMPCLj45/OQ54IBHnSL5JCsAKC1Y8pcUZisvFVK9MD/xN olX+gKRL5eV/ZKhgL05LrYupvGJ/SdfWUB3V7SpqncUeawDcwsT1N2kHbDln2fKFNF+V VpQ65swxM6sFbu9HzX0NzltBVo3XlGaMxMPHypD6ByB+jW5d4kuK1vnGCvqkLQDcUZI7 OiBI0Om2+ZN7aaRMTXKGx5w7JqPPwr2XYf7m+WMgfwdWRBuOSHliTEAs/a/CviAPNFFE 7x5jqiOmqmlAQUBnqsOKp30fFtPbr5pX4rc/5kmtuH+0fau8DmeP/EY07zJLn4Ej2AGX gJdQ== X-Gm-Message-State: APjAAAUvHJluv75J4TLOYdeiJ02mKLKvz01PGzYbfwaqiSIfKqvlrLuu 8yUre0BPCynQKwv7f+aFt4c= X-Google-Smtp-Source: APXvYqxJq1WbS2DBxAHVPR59NM3DZHjm6j4bnWQpGwhVVbZ07V0gQZ5xhzu5Kt45G8iYbCONeB0dqQ== X-Received: by 2002:a17:90a:930f:: with SMTP id p15mr10170606pjo.2.1577241412487; Tue, 24 Dec 2019 18:36:52 -0800 (PST) Received: from localhost.localdomain (114-34-112-171.HINET-IP.hinet.net. [114.34.112.171]) by smtp.gmail.com with ESMTPSA id u18sm27245406pgi.44.2019.12.24.18.36.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 24 Dec 2019 18:36:52 -0800 (PST) From: Jun Chen To: laurent.pinchart@ideasonboard.com Cc: mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, ptchentw@gmail.com, Jun Chen Subject: [PATCH] media: uvcvideo: Fix annotation for uvc_video_clock_update() Date: Wed, 25 Dec 2019 10:34:17 +0800 Message-Id: <1577241257-9203-1-git-send-email-ptchentw@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Jun Chen The formula (2) is to convert from SOF to host clock, it should be fix as "TS = ((TS2 - TS1) * SOF + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1)" Signed-off-by: Jun Chen Reviewed-by: Laurent Pinchart --- drivers/media/usb/uvc/uvc_video.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 8fa77a8..a3150da 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -622,7 +622,7 @@ static u16 uvc_video_clock_host_sof(const struct uvc_clock_sample *sample) * to avoid losing precision in the division. Similarly, the host timestamp is * computed with * - * TS = ((TS2 - TS1) * PTS + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1) (2) + * TS = ((TS2 - TS1) * SOF + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1) (2) * * SOF values are coded on 11 bits by USB. We extend their precision with 16 * decimal bits, leading to a 11.16 coding.