Raspberry Pi 3: a small rainbow square on the top right of screen

[gerald.yang]

I'm working on the WD/nextcloud project, and found this issue

Download the UC16 for Raspberry Pi 3 from http://releases.ubuntu.com/ubuntu-core/16/ubuntu-core-16-pi3.img.xz
unxz , dd the image to sd card and boot up the system.
There is a small rainbow square on top right of HDMI monitor.

From RPI forum: https://www.raspberrypi.org/forums/viewtopic.php?t=82373
If the voltage is under 4.65V, firmware displays a rainbow square on top right of screen and power LED goes off.
But for UC16 the rainbow square is always there even the voltage is sufficient, but the power LED works properly.

So I also check
1. Ubuntu server for RPI3 from here: https://wiki.ubuntu.com/ARM/RaspberryPi
    This RPI3 image works properly (if the voltage is not sufficient, rainbow square shows on the top right of screen, if it's sufficient,
    no rainbow square shows up)
 2. Rasbian (jessie lite): https://downloads.raspberrypi.org/raspbian_lite_latest
    This works properly too, and the official Rasbian was released with the latest firmware, so the rainbow square changes to a
    lighting icon

It looks the firmware might be old in UC16? so the under-voltage warning doesn't display correctly.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1647936

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Ying-Chun Liu (paulliu)]

So, according to the forum, we should try this commit.

https://github.com/raspberrypi/firmware/commit/db63c10c2b3e7196b74e386ea6ae6b52c4a6be83

[Oliver Grawert (ogra)]

the gadget snap in edge has this fix since a while already, it just did not make it into a stable image yet.

[Oliver Grawert (ogra)]

https://github.com/snapcore/pi3-gadget/commit/8b88f06ab5681d0ff41704a7813665a0203cbafc for reference

[Anthony Wong (anthonywong)]

Oliver, who is responsible for promoting the gadget snap to stable channel?

[Ying-Chun Liu (paulliu)]

Hi.

I tried to
"snap refresh pi3 --channel=edge"
"snap refresh pi2-kernel --channel=edge"

The rainbow square is still appeared. Is this the correct way to upgrade gadgets and put the firmwares onto the system?

# snap info pi3
name: pi3
summary: "Raspberry Pi 3 support package"
publisher: canonical
description: |
  Support files for booting Raspberry Pi

type: gadget
tracking: edge
installed: 16.04-0.5 (14) 6MB -
refreshed: 2017-01-18 15:02:58 +0000 UTC
channels:
  stable: 16.04-0.5 (6) 6MB -
  candidate: 16.04-0.5 (6) 6MB -
  beta: 16.04-0.5 (6) 6MB -
  edge: 16.04-0.5 (14) 6MB -

# snap info pi2-kernel
name: pi2-kernel
summary: "The canonical raspi2 armhf kernel"
publisher: canonical
description: |
  The Ubuntu linux-raspi2 kernel package as a snap
type: kernel
tracking: edge
installed: 4.4.0-1040-47 (26) 101MB -
refreshed: 2017-01-11 11:52:04 +0000 UTC
channels:
  stable: 4.4.0-1030-3 (22) 89MB -
  candidate: 4.4.0-1030-3 (22) 89MB -
  beta: 4.4.0-1044-51 (27) 100MB -
  edge: 4.4.0-1040-47 (26) 101MB -

[Ying-Chun Liu (paulliu)]

I think I'm making wrong assumption? It seems to me that refresh gadget snaps won't upgrade the files in the system.
Upgrading kernel snap does change the kernel/uboot.env stuff. But not for gadgets right? Seems we need to regenerate an edge image for testing this?

[Oliver Grawert (ogra)]

@anthony ... technically that would be me ... practically the gadget will never update the firmware files (the firmware files as well as the dtb are usually in a dead-lock with the kernel version)

i'm waiting for a solution for this from the core team before we can move on ... your best bet is to use edge based images (kernel and gadget) for the moment.

[Oliver Grawert (ogra)]

@ying-chun the kernel snap only upgrades the kerne, modules and files in /lib/firmware ...

the gadget snap only updates the gadget.yaml, snap.yaml and files not in /boot (i.e. it excludes all bootloader bits by default). until there is a solution for potential unbootable systems this will not change i fear.

[Ying-Chun Liu (paulliu)]

I've tried manually copy the binary blobs into /boot and the rainbow square disappeared. And when the power is not enough it displayed a "lightning" icon. So if we rebuild an image based on the gadget in edge channel we should be able to fix the problem.

[Zygmunt Krynicki (zyga)]

> Wiadomość napisana przez Ying-Chun Liu <email address hidden> w dniu 13.03.2017, o godz. 11:02:
>
> I think I'm making wrong assumption? It seems to me that refresh gadget snaps won't upgrade the files in the system.

That is correct. This is not yet supported by snapd.

> Upgrading kernel snap does change the kernel/uboot.env stuff. But not for gadgets right? Seems we need to regenerate an edge image for testing this?
>
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[gerald.yang (gerald-yang-tw)]

@Zygmunt

So does it mean even I add a configure hook in meta/hooks/ to copy those binaries to boot partition (/boot/uboot/),
there is no such interface in snapd to allow this?
Thanks

[Oliver Grawert (ogra)]

@gerald: right, there is no way to protect you from turning the device into a brick if this step goes wrong (unlike kernel or rootfs we can not roll back the bootloader)

note that the gadget snap from edge will not have a working dtb for the old kernel which will likely make you end up with an unbootable device. sadly on the pi the dtb gets loaded by the binary blob which is why we can not just use it from the kernel snap (which would fix this problem).