Tried on both 5.17 and 5.20, Debian and Ubuntu with legacy kernel. Debian has systemd 215, Ubuntu has 225 iirc.

 

If I plug an iphone usbmuxd is started by systemd-udevd as directed by udev rule (stock one) and gets shut down when I unplug it, again how it's supposed to be. The problem is, it does not start if I plug any Apple device again. Restarting systemd-udevd service does not help at all, and when I reboot the board usbmuxd gets started when I plug iphone but again only once.

 

1st plug in/plug off in syslog:

Sep 19 09:26:57 localhost kernel: [   90.005422] ehci_irq: port change detect
Sep 19 09:26:57 localhost kernel: [   90.279798] usb 2-1: new high-speed USB device number 2 using sw-ehci
Sep 19 09:26:57 localhost systemd[1]: Started Socket daemon for the usbmux protocol used by Apple devices.
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.922][3] usbmuxd v1.1.0 starting up
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.928][3] Successfully dropped privileges to 'usbmux'
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.945][3] Could not get old configuration descriptor for device 2-2: -5
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.949][3] Connecting to new device on location 0x20002 as ID 1
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.950][3] Initialization complete
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.950][3] Enabled exit on SIGUSR1 if no devices are attached. Start a new instance with "--exit" to trigger.
Sep 19 09:26:57 localhost usbmuxd[1070]: [09:26:57.950][3] Connected to v2.0 device 1 on location 0x20002 with serial number 4d97a270aba9ba766a13989d9a90caa806d31b6b
Sep 19 09:26:58 localhost kernel: [   90.768031] ipheth 2-1:4.2: Apple iPhone USB Ethernet device attached
Sep 19 09:26:58 localhost kernel: [   90.775448] usbcore: registered new interface driver ipheth

Sep 19 09:28:27 localhost kernel: [  180.016143] ehci_irq: port change detect
Sep 19 09:28:27 localhost kernel: [  180.020243] usb 2-1: USB disconnect, device number 2
Sep 19 09:28:27 localhost usbmuxd[1070]: [09:28:27.212][3] Removed device 1 on location 0x20002
Sep 19 09:28:27 localhost kernel: [  180.077995] ipheth 2-1:4.2: Apple iPhone USB Ethernet now disconnected
Sep 19 09:28:27 localhost usbmuxd[1070]: [09:28:27.275][3] usbmuxd shutting down
Sep 19 09:28:27 localhost usbmuxd[1070]: [09:28:27.376][3] Shutdown complete

Then the same device plugged in:

Sep 19 09:29:31 localhost kernel: [  244.610407] ehci_irq: port change detect
Sep 19 09:29:32 localhost kernel: [  244.878100] usb 2-1: new high-speed USB device number 3 using sw-ehci

And that's all.

 

This works on amd64 Ubuntu 16.04 as expected.

 

EDIT: usbmuxd is properly started by systemd-udevd on Jessie vanilla, so this seems related to kernel.

 

EDIT2: board is Banana Pro.

Any hints where should I look for clues?

Works fine on Bananian with 3.4.112 kernel so it might be related to Armbian build. Or is related to systemd-udevd because Bananian does not use systemd, usbmuxd is started from plain udevd.

# uname -a
Linux bananapi 3.4.112-bananian #6 SMP PREEMPT Fri May 13 18:21:01 UTC 2016 armv7l GNU/Linux

Here's the diff. I have no idea which options play any role in the problem.

 

http://pastebin.com/rPYs5ugn

This is not related to hardware, result is exactly the same on 5.20 on H3 device with legacy kernel.