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=-15.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 1EF85C433E2 for ; Wed, 16 Sep 2020 00:06:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C969F21D24 for ; Wed, 16 Sep 2020 00:06:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600214778; bh=DwLkYfmvYqguFFhhJqxU6FsNbRSd9t4OArP9WW2CiEM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aNvhVeLtvVjJWGUQYKdwdiSByHU8Wah3Ncn2Bt5n4M+QIuRbkNoDD5C6kl3+xrv25 jrbbvUZkdln1+SbZGW3gjjpxT6/pXqQ2Xp5X8f1ocPseUadiQQPSj8hDpOfjnKz24N yQ1PwlG4kqOmiWozpzgrAX5Ds+/iBeTQr3OeieEM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727382AbgIPAGQ (ORCPT ); Tue, 15 Sep 2020 20:06:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:42986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726844AbgIOO27 (ORCPT ); Tue, 15 Sep 2020 10:28:59 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 30C472223E; Tue, 15 Sep 2020 14:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179656; bh=DwLkYfmvYqguFFhhJqxU6FsNbRSd9t4OArP9WW2CiEM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wKqvBc3Ke11VGvpP+YDy581OOAQN97exDw4wnZW5jAO/OZUlP1g+bHwwpqDRpCln1 nWoOKBMVRGMkylW+kJtIUoAi86UJ8zR2kc+ZrG13CCwJVWSMM7K9S/rRCY0JK+waP9 hoyKcq25xPnV0IUI4tV1HdThVyiSCsLLYa6eYFEI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Douglas Anderson , Veerabhadrarao Badiganti , Adrian Hunter , Ulf Hansson , Sasha Levin Subject: [PATCH 5.4 026/132] mmc: sdhci-msm: Add retries when all tuning phases are found valid Date: Tue, 15 Sep 2020 16:12:08 +0200 Message-Id: <20200915140645.407529458@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Douglas Anderson [ Upstream commit 9d5dcefb7b114d610aeb2371f6a6f119af316e43 ] As the comments in this patch say, if we tune and find all phases are valid it's _almost_ as bad as no phases being found valid. Probably all phases are not really reliable but we didn't detect where the unreliable place is. That means we'll essentially be guessing and hoping we get a good phase. This is not just a problem in theory. It was causing real problems on a real board. On that board, most often phase 10 is found as the only invalid phase, though sometimes 10 and 11 are invalid and sometimes just 11. Some percentage of the time, however, all phases are found to be valid. When this happens, the current logic will decide to use phase 11. Since phase 11 is sometimes found to be invalid, this is a bad choice. Sure enough, when phase 11 is picked we often get mmc errors later in boot. I have seen cases where all phases were found to be valid 3 times in a row, so increase the retry count to 10 just to be extra sure. Fixes: 415b5a75da43 ("mmc: sdhci-msm: Add platform_execute_tuning implementation") Signed-off-by: Douglas Anderson Reviewed-by: Veerabhadrarao Badiganti Acked-by: Adrian Hunter Link: https://lore.kernel.org/r/20200827075809.1.If179abf5ecb67c963494db79c3bc4247d987419b@changeid Signed-off-by: Ulf Hansson Signed-off-by: Sasha Levin --- drivers/mmc/host/sdhci-msm.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index 84cffdef264b7..8bed81cf03adc 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -1096,7 +1096,7 @@ static void sdhci_msm_set_cdr(struct sdhci_host *host, bool enable) static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode) { struct sdhci_host *host = mmc_priv(mmc); - int tuning_seq_cnt = 3; + int tuning_seq_cnt = 10; u8 phase, tuned_phases[16], tuned_phase_cnt = 0; int rc; struct mmc_ios ios = host->mmc->ios; @@ -1152,6 +1152,22 @@ retry: } while (++phase < ARRAY_SIZE(tuned_phases)); if (tuned_phase_cnt) { + if (tuned_phase_cnt == ARRAY_SIZE(tuned_phases)) { + /* + * All phases valid is _almost_ as bad as no phases + * valid. Probably all phases are not really reliable + * but we didn't detect where the unreliable place is. + * That means we'll essentially be guessing and hoping + * we get a good phase. Better to try a few times. + */ + dev_dbg(mmc_dev(mmc), "%s: All phases valid; try again\n", + mmc_hostname(mmc)); + if (--tuning_seq_cnt) { + tuned_phase_cnt = 0; + goto retry; + } + } + rc = msm_find_most_appropriate_phase(host, tuned_phases, tuned_phase_cnt); if (rc < 0) -- 2.25.1