From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley 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) Date: Tue, 5 Apr 2016 17:24:57 -0700 Message-ID: <57045759.70308@hurleysoftware.com> References: <57008645.4070808@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Ulf Hansson Cc: Linus Torvalds , linux-mmc , Adrian Hunter , "linux-kernel@vger.kernel.org" , Jaehoon Chung List-Id: linux-mmc@vger.kernel.org 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