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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41420C83F3F for ; Mon, 4 Sep 2023 14:28:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353148AbjIDO2v (ORCPT ); Mon, 4 Sep 2023 10:28:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350965AbjIDO2r (ORCPT ); Mon, 4 Sep 2023 10:28:47 -0400 Received: from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com [IPv6:2a00:1450:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7772CFB for ; Mon, 4 Sep 2023 07:28:42 -0700 (PDT) Received: by mail-ed1-x52e.google.com with SMTP id 4fb4d7f45d1cf-52a39a1c4d5so2042040a12.3 for ; Mon, 04 Sep 2023 07:28:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693837721; x=1694442521; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=8iuZC33D0pi0SebavXErWmT+pulYIQNcxBHdRQcQik8=; b=i+NrAXlD4u8Ng1VlPXus3DUIWmOtAqb2VmhucPV+g77Tay/c1zJ9yS4cUkxasvsB5m 2GIsDJV0hczfbL/H4dJdeYX8txCVPtug3RXXpGq7KUw04cEC9cTB2fsMf82ODkCHfOMy PIlUlDeFeElL2g771ZAstt3XFWQvUyPR4pAKSi/QZ2UPaqHQYuEZzfL4rP3yx7IzzG73 YCqPywnmxDr6DZfOn7L5Rl4DuoXE/Kak2HeK080utwKT2p++qVyYc5+QYJozI9jN3HKN Xx5B5QnnhVsYSRlN2heUmArF3aTYY+FbuIoYg4BPZjcp3FvEOmE2XXxBxbByzpXC/tbX 8+gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693837721; x=1694442521; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8iuZC33D0pi0SebavXErWmT+pulYIQNcxBHdRQcQik8=; b=g2g222x38vnV4thR5lAcFMN3c+yNsP6M9WQCr1ISUSFwb6oyYtII5ybkSlWpE0Fpkn NE4hJBboLpZf0OwVUfosVAQzS4nz2ud0SGePBeWVUQDWPjQHSqRu3TZmvE4JOB1l2eUo x+2O2UuAzj9wslZSFGFZomcN3F0BfRdvdgVnkqUi45P3+7BdLmZA/YlTXd2sKAFamWm3 L7w251IuKZfFarOs2SwlK0vlLrgn9mJ7lvGkaM0acdCrp1uc8pEbHw/ilxr2GuV7Cf+p 7QCWmyqsUcZMWZo2m0whL+EudTtIrQHTFd57z0PiYM010Lr14GNOuxWVupMj0T1NxH51 6Wgg== X-Gm-Message-State: AOJu0YxjwHFQSfDsSUbDcvCAVVeDAkuLuhy2WXLMqLTpdHbJEoGFpgOp UNNMvBLBq7A37GHWj8Oq398= X-Google-Smtp-Source: AGHT+IFskoTClGeTBvqu3n1vQK3DtrW+gFUuQJHiyBXfyIZHMy7jeXQO/PenDGkfjW4bANcjhDq1CQ== X-Received: by 2002:aa7:d407:0:b0:52a:3ee9:a786 with SMTP id z7-20020aa7d407000000b0052a3ee9a786mr6642621edq.26.1693837720880; Mon, 04 Sep 2023 07:28:40 -0700 (PDT) Received: from ?IPV6:2a02:908:8b3:1840:e0a4:c719:5e8d:3b55? ([2a02:908:8b3:1840:e0a4:c719:5e8d:3b55]) by smtp.gmail.com with ESMTPSA id e11-20020a056402148b00b00529fa63ef6fsm5930777edv.57.2023.09.04.07.28.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Sep 2023 07:28:40 -0700 (PDT) Message-ID: <53ee3d14-05f4-981f-26d2-ef9ef6b3a61b@gmail.com> Date: Mon, 4 Sep 2023 16:28:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH 5/5] drm/bridge: samsung-dsim: calculate porches in Hz To: Michael Tretter Cc: kernel@pengutronix.de, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Inki Dae , Jagan Teki , Marek Szyprowski , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , David Airlie , Daniel Vetter References: <20230818-samsung-dsim-v1-0-b39716db6b7a@pengutronix.de> <20230818-samsung-dsim-v1-5-b39716db6b7a@pengutronix.de> Content-Language: en-US From: Maxim Schwalm In-Reply-To: <20230818-samsung-dsim-v1-5-b39716db6b7a@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 28.08.23 17:59, Michael Tretter wrote: > Calculating the byte_clk in kHz is imprecise for a hs_clock of 55687500 > Hz, which may be used with a pixel clock of 74.25 MHz with mode > 1920x1080-30. > > Fix the calculation by using HZ instead of kHZ. > > This requires to change the type to u64 to prevent overflows of the > integer type. > > Signed-off-by: Michael Tretter > --- > drivers/gpu/drm/bridge/samsung-dsim.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c > index 459be953be55..eb7aca2b9ab7 100644 > --- a/drivers/gpu/drm/bridge/samsung-dsim.c > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c > @@ -973,10 +973,12 @@ static void samsung_dsim_set_display_mode(struct samsung_dsim *dsi) > u32 reg; > > if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) { > - int byte_clk_khz = dsi->hs_clock / 1000 / 8; > - int hfp = DIV_ROUND_UP((m->hsync_start - m->hdisplay) * byte_clk_khz, m->clock); > - int hbp = DIV_ROUND_UP((m->htotal - m->hsync_end) * byte_clk_khz, m->clock); > - int hsa = DIV_ROUND_UP((m->hsync_end - m->hsync_start) * byte_clk_khz, m->clock); > + u64 byte_clk = dsi->hs_clock / 8; > + u64 pix_clk = m->clock * 1000; > + > + int hfp = DIV64_U64_ROUND_UP((m->hsync_start - m->hdisplay) * byte_clk, pix_clk); > + int hbp = DIV64_U64_ROUND_UP((m->htotal - m->hsync_end) * byte_clk, pix_clk); > + int hsa = DIV64_U64_ROUND_UP((m->hsync_end - m->hsync_start) * byte_clk, pix_clk); Wouldn't it make sense to use the videomode structure here? > > /* remove packet overhead when possible */ > hfp = max(hfp - 6, 0); > Best regards, Maxim