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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 C085CC48BD1 for ; Thu, 10 Jun 2021 14:48:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8187613E3 for ; Thu, 10 Jun 2021 14:48:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231428AbhFJOuR (ORCPT ); Thu, 10 Jun 2021 10:50:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230298AbhFJOuP (ORCPT ); Thu, 10 Jun 2021 10:50:15 -0400 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8568C061574; Thu, 10 Jun 2021 07:48:06 -0700 (PDT) Received: by mail-wm1-x329.google.com with SMTP id l18-20020a1ced120000b029014c1adff1edso6727390wmh.4; Thu, 10 Jun 2021 07:48:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=D/ihjXO4RqE7jX7suSjDihZYCxFd3H0ms2fk8B+1vrY=; b=r9aCM9AHb8JpMAdzpnuIG/pJhJkaOVrMX09Mz+tP7L5ahdd51MuGMJBZ7ltUxxNN32 kkmrAarwMbcwPlLQMDF9/+2/d5CudUoTqWLfobzSqEKEWITkDQnUpgq6I/bPmWAiUJxF cHQwkZn6oYYYyENrQuX3xtQMLeMRhIILcyapldrzkApmrwTTJRRxb/EZb0WKv1+agi6y Kzuv8ntPYyRGyNFesU+HYqB1cbFErbX13tEXxUOfRnSOGMF8DZPz2nGrIySRF86guCaj eMy1FFOTD/L3mGHT/9usARui+NqlbvMZ1+TRBwO3liFoiUBXvwFwUUuNSvSQjo4+w/qT NlGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=D/ihjXO4RqE7jX7suSjDihZYCxFd3H0ms2fk8B+1vrY=; b=X44iHVIQK7wE2KNKA0QP6/p/W8fm1BnOq5P/b3XU/jyFkELBppEKdi1hIof/w4qwCG NPi90siFfZMM9Bd38cTzXjnCvsDoVYBlhu39T+h3yA996l2s6y/zm+KQBjsln/BqLGdQ PkMmmWL0JROldglHXmIGlpYP02xDjUFJFf47W0/gc7PHtY01brNGECLUiTZMQb7UxVr8 LRDH4xrnt6tI20EDHI0kHk7b+Waq00lSJ6ynC7jHuIIK+8/Tsg/lY20qOSn/TS7WZL7H 7hTb+WWV+/+GaZiNKob2uWWqK1mgDwvGvCbk7/h+ZDwUHactIctsETEcMV027PBnxL/7 REYA== X-Gm-Message-State: AOAM532O3ZdFfwk6IoxvHAmr9GpenRyu8bzLdblzCVwR5Np7g2FXcbEk xmoC9GlNxlMQafFQSdnzQIu9I6I6kgQ+1IUyz7I= X-Google-Smtp-Source: ABdhPJxs+Nw9AecB4n5d4NRAI3Sze1CREk1iqKnLbtL7oryF5BI7b2gh+Dmm/XxLsQJnB6KluTS30+Rjsn/w3RtRtPA= X-Received: by 2002:a05:600c:1c84:: with SMTP id k4mr15648966wms.164.1623336485064; Thu, 10 Jun 2021 07:48:05 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Rob Clark Date: Thu, 10 Jun 2021 07:51:58 -0700 Message-ID: Subject: Re: Re : Query on UFS Lun detection To: vhiren@codeaurora.com Cc: Bjorn Andersson , adrian.hunter@intel.com, Rob Herring , Ulf Hansson , Asutosh Das , stummala@codeaurora.org, sayalil@codeaurora.org, rampraka@codeaurora.org, vbadigan@codeaurora.org, Stephen Boyd , Georgi Djakov , Matthias Kaehlcke , linux-mmc@vger.kernel.org, Linux Kernel Mailing List , linux-arm-msm , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Andy Gross , linux-mmc-owner@vger.kernel.org, nitirawa@codeaurora.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Jun 10, 2021 at 6:28 AM wrote: > > Hi Community, > > We are using UFS as a boot device, and we encountered an error, > mentioned below while booting through UFS. > > > APPS Crash - Kernel panic - not syncing: VFS: Unable to mount root fs on > unknown-block(8,7) > > Here in Kernel command line we are passing "root=3Dsda7", this is our > Filesystem partition to be mounted. > > While debugging the same we observed the partition which is suppose to > be mounted as Filesystem is not enumerated itself. > The reason behind not enumerating of partition is, the other Lun got > detected first instead of one which is having FS partition. Use the UUID or PARTUUID instead, ie: root=3DUUID=3D13846802-672b-4a5d-9f0a-22d13957add3 (but you'd have to check the actual UUID of your partition with a tool like blkid BR, -R > We are using async probe, hence we know the detection will happen in > async way, > > > In working case : it looks like below > > sd 0:0:0:0: sda1 sda2 sda3 sda4 =E2=80=A6..sda8 > > sd 0:0:0:1: sdb1 sdb2 > Here, sd 0:0:0:0 Lun got detected first and enumerated as "sdaN", we > have FS partition as "sda7" and so we don=E2=80=99t see above mentioned e= rror. > > > In non working case : it looks like below > > sd 0:0:0:0: sdb1 sdb2 sdb3 sdb4 =E2=80=A6..sdb8 > > sd 0:0:0:1: sda1 sda2 > Here, sd 0:0:0:1 Lun got detected first and enumerated as "sdaN" but we > don=E2=80=99t have FS partition in this Lun. Instead FS partition now bec= ame > "sdb7". > > > Observation here is, which ever Lun gets detected first it will have > "sda" enumeration and so on. > However, sdx=E2=80=99s driver scsi/sd.c uses async probe to improve perfo= rmance, > meaning sdx disks are created in parallel. Whoever calls > device_add_disk() first becomes sda, the next become sdb=E2=80=A6. > > > Is there any way, where we can fix this in the Lun detection part of > code? > > Thank You, > Regards, > Hiren Gohel