Wandboard i.MX6 Quad Board has different boot device

[Benjamin Drung]

== Rationale ==
The wandboards have two microsd slots, one directly tied to the SoC and one on the main board. The wandboard only boots from the one tied to the SoC.

Unfortunately, the device numbering is wrong, in that when only the SoC slot is populated, it'll appear as mmcblk0, but when both slots are, the SoC slot becomes mmcblk1.

So far flash-kernel has only supported the configuration with both slots populated, but it's reasonably common for people to only use the SoC slot and then use the SATA port to attach more storage.

The fix is to use the constant path name from udev which always points to the right slot.

== Testcase ==
 - Run flash-kernel before update => fails to find sdcard
 - Run flash-kernel after update => finds sdcard and install kernel
 - Reboot to check that things boot as expected

== Regression potential ==
Should a system somehow miss the /dev/disk/by-path symlink, flash-kernel may fail to install the new kernel. Note that testing on 5 different boards showed that this symlink is constant, regardless of storage configuration, so this shouldn't be an actual problem.

== Original bug report ==
The Wandboard i.MX6 Quad Board has two sdcard slots. The boot device is set to "/dev/mmcblk1p1", but this device only exists if both sdcard slots are used. I use just one sdcard and my boot device is called "/dev/mmcblk0p1".

flash-kernel need to dynamically detect the correct sdcard slot or use a unique device name.

I have following device symlink on my system:
/dev/disk/by-id/mmc-SD16G_0xd62aac9a-part1
/dev/disk/by-path/platform-2198000.usdhc-part1
/dev/block/179:1

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Stéphane Graber (stgraber)]

I just uploaded a fix to wily which should fix that.

I'll SRU it back to trusty too.

[Stéphane Graber (stgraber)]

Fixes uploaded to the trusty and vivid queues.

[Brian Murray (brian-murray)]

Hello Benjamin, or anyone else affected,

Accepted flash-kernel into vivid-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/flash-kernel/3.0~rc.4ubuntu54.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Brian Murray (brian-murray)]

Hello Benjamin, or anyone else affected,

Accepted flash-kernel into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/flash-kernel/3.0~rc.4ubuntu49.6 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Michael Jeanson (mjeanson)]

I tested 3.0~rc.4ubuntu49.6 in trusty-proposed and I confirm I can now run flash-kernel successfully on a Wandboard Quad without manually editing all.db

[Stéphane Graber (stgraber)]

and I just validated vivid too (installed on trusty though).

[Launchpad Janitor (janitor)]

This bug was fixed in the package flash-kernel - 3.0~rc.4ubuntu49.6

---------------
flash-kernel (3.0~rc.4ubuntu49.6) trusty; urgency=medium

  * Wandboard: Use /dev/disk/by-path/platform-2198000.usdhc-part1
    instead of the hardcoded mmcblk1p1, this should make things work on
    boards with just a single microSD card in. (LP: #1306841)

 -- Stéphane Graber <email address hidden> Thu, 27 Aug 2015 12:07:33 -0400

[Chris Halse Rogers (raof)]

The verification of the Stable Release Update for flash-kernel has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package flash-kernel - 3.0~rc.4ubuntu54.1

---------------
flash-kernel (3.0~rc.4ubuntu54.1) vivid; urgency=medium

  * Wandboard: Use /dev/disk/by-path/platform-2198000.usdhc-part1
    instead of the hardcoded mmcblk1p1, this should make things work on
    boards with just a single microSD card in. (LP: #1306841)

 -- Stéphane Graber <email address hidden> Thu, 27 Aug 2015 12:06:16 -0400