Re: [PATCH v2 0/4] Patches to allow consistent mmc / mmcblk numbering w/ device tree

From: Rob Herring
Date: Wed May 04 2016 - 08:26:13 EST

On Wed, May 4, 2016 at 2:18 AM, Pavel Machek <pavel@xxxxxx> wrote:
> On Fri 2016-04-29 19:12:48, Russell King - ARM Linux wrote:
>> On Fri, Apr 29, 2016 at 10:32:15AM -0700, Douglas Anderson wrote:
>> > This series picks patches from various different places to produce what
>> > I consider the best solution to getting consistent mmc and mmcblk
>> > ordering.
>> >
>> > Why consistent ordering and why not just use UUIDs? IMHO consistent
>> > ordering solves a few different problems:
>> NAK. Really. Use UUIDs, that's the proper solution here.
> Except that UUIDs do not solve the problem.
> You have just booted of nfsroot, and you want to format u-SD card in
> the external slot. How do you do that?

The same way you format a USB stick when you insert it.

If you have built-in versus removable, then we should expose that
information to userspace rather than some arbitrary encoding in DT
that 0 means built-in and 1 means removable. Or if you have multiple
slots, then use "label" to provide meaningful slot names.