Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760205AbcDFAZF (ORCPT ); Tue, 5 Apr 2016 20:25:05 -0400 Received: from mail-pf0-f179.google.com ([209.85.192.179]:35971 "EHLO mail-pf0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753912AbcDFAZC (ORCPT ); Tue, 5 Apr 2016 20:25:02 -0400 Subject: Re: [bisect] Merge tag 'mmc-v4.6' of git://git.linaro.org/people/ulf.hansson/mmc (was [GIT PULL] MMC for v.4.6) To: Ulf Hansson References: <57008645.4070808@hurleysoftware.com> Cc: Linus Torvalds , linux-mmc , Adrian Hunter , "linux-kernel@vger.kernel.org" , Jaehoon Chung From: Peter Hurley Message-ID: <57045759.70308@hurleysoftware.com> Date: Tue, 5 Apr 2016 17:24:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 839 Lines: 20 On 04/05/2016 01:59 AM, Ulf Hansson wrote: > Although, what puzzles me around this particular issue, is how an SoC > configuration can rely on this fragile behaviour. > All you have to do to break the assumption of fixed mmcblk ids, is to > boot with an SD card inserted and then without. Perhaps these SoCs > just doesn't support this use case!? Both configurations boot reliably; without the uSD inserted, the boot and root partitions on the eMMC are booted instead. Without a uSD inserted, the only mmc block device is the eMMC which is /dev/mmcblk0, and the root partition is still /dev/mmcblk0p2. Note though that this particular bootscript can load add'l bootscripts from the boot partition; in this particular case, the eMMC root partition is set as a fixed UUID in the bootscript from the boot partition. Regards, Peter Hurley