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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 B0331C432C3 for ; Sat, 16 Nov 2019 16:02:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83683206C0 for ; Sat, 16 Nov 2019 16:02:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573920144; bh=uOQtTCLHEwtW2ut6Q0nPb0g093HpDJgAfOS0CS1GpVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=R2PODoDsFYmGTrEvcpmscvuaOQ/ZMdZV8sZWjrrTqR2d0UVj7wCxWosUwCwU5AeTW gN0PsPFNFHdc6MJ6iTji0IoiyE0vZoi1GMmoVGL+puDGjfI3XaWxKQ4/sUkHW4M/qg oGdu29f/QltTrASJ7V17ALcBH8iSmGJgES+N8zIg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731414AbfKPQCW (ORCPT ); Sat, 16 Nov 2019 11:02:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:33820 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727709AbfKPPw6 (ORCPT ); Sat, 16 Nov 2019 10:52:58 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7C5DB20871; Sat, 16 Nov 2019 15:52:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919578; bh=uOQtTCLHEwtW2ut6Q0nPb0g093HpDJgAfOS0CS1GpVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MPXl1wM/3dcu9uSFWGOfJuF/DMDY92BY5ZfC8alYbttcWzJ7dOLhuZgJhO1s48Y7d JeRJLD+Q++Bubl6trSTTe13onecU79lj327eyzFbPKFLjAOufzmLS4HRDnUqDAA3CW NHkRe8uy87ESi8/EQ25F+QjXxPq/1hSQ3vh3H4VM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miroslav Lichvar , Jacob Keller , Richard Cochran , Thomas Gleixner , Aaron Brown , Jeff Kirsher , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 69/99] igb: shorten maximum PHC timecounter update interval Date: Sat, 16 Nov 2019 10:50:32 -0500 Message-Id: <20191116155103.10971-69-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116155103.10971-1-sashal@kernel.org> References: <20191116155103.10971-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miroslav Lichvar [ Upstream commit 094bf4d0e9657f6ea1ee3d7e07ce3970796949ce ] The timecounter needs to be updated at least once per ~550 seconds in order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old timestamp. Since commit 500462a9d ("timers: Switch to a non-cascading wheel"), scheduling of delayed work seems to be less accurate and a requested delay of 540 seconds may actually be longer than 550 seconds. Shorten the delay to 480 seconds to be sure the timecounter is updated in time. This fixes an issue with HW timestamps on 82580/I350/I354 being off by ~1100 seconds for few seconds every ~9 minutes. Cc: Jacob Keller Cc: Richard Cochran Cc: Thomas Gleixner Signed-off-by: Miroslav Lichvar Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/igb/igb_ptp.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c index 9eb9b68f8935e..ae1f963b60923 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -65,9 +65,15 @@ * * The 40 bit 82580 SYSTIM overflows every * 2^40 * 10^-9 / 60 = 18.3 minutes. + * + * SYSTIM is converted to real time using a timecounter. As + * timecounter_cyc2time() allows old timestamps, the timecounter + * needs to be updated at least once per half of the SYSTIM interval. + * Scheduling of delayed work is not very accurate, so we aim for 8 + * minutes to be sure the actual interval is shorter than 9.16 minutes. */ -#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9) +#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 8) #define IGB_PTP_TX_TIMEOUT (HZ * 15) #define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT) #define INCVALUE_82576_MASK GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0) -- 2.20.1