XU4 persistent power to USB 3 during reboot [SOLVED]

Test and fix the Kernel 4.14 features

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XU4 persistent power to USB 3 during reboot [SOLVED]

Unread postby CalebCarroll » Wed Aug 30, 2017 8:09 am

I've noticed a bit of weird behaviour relating the the USB 3 ports on the XU4:

Firstly, power to the USB 3.0 ports is persistent meaning that a USB device connected to these ports remains powered on during a reboot. Power to the USB 2.0 port is disconnected during reboot.
- I'm wondering if anyone knows if there is a way to get the XU4 to disconnect power to the USB 3 ports during reboot?

Secondly, if I have 2 devices connected to the USB 3.0 ports, when I apply power to the XU4 (not a reboot) the devices will be reset within 30 seconds of booting. dmesg & syslog show usb 3-1 USB Disconnect followed by the two sub-devices 3-1.1 3-1.2. The devices are re-detected, re-enumerated and there are no further problems. If I connect one of the devices to the USB 2.0 port I don't see this behavour (at least not yet).
- I'm assuming this is just another (or possibly duplicate) XU4 USB 3.0 port issue that's already been reported?

I'm running Ubuntu 16.04 with kernel 4.9.44-56 BTW

Thanks,
Caleb
Last edited by CalebCarroll on Thu Sep 14, 2017 1:52 am, edited 1 time in total.
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Re: XU4 persistent power to USB 3 during reboot

Unread postby odroid » Thu Aug 31, 2017 9:51 am

USB 3.0 hub IC (GL3521) on the XU4 board resets the load switches in the kernel boot process.
USB 2.0 port is directly connected to the CPU and there is no reset event in the boot process.
So your observation is very normal.
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Re: XU4 persistent power to USB 3 during reboot

Unread postby CalebCarroll » Sun Sep 03, 2017 2:55 am

odroid wrote:USB 3.0 hub IC (GL3521) on the XU4 board resets the load switches in the kernel boot process.
USB 2.0 port is directly connected to the CPU and there is no reset event in the boot process.
So your observation is very normal.


If the USB 3.0 hub is resetting the load switches during the boot process then why is this effecting the USB device after booting is complete? The USB device is operational for a random period of time after booting is complete (typically 30 seconds to 1.5 minutes) but it will then suddenly lose power / disconnect.

When the same USB device is connected to the USB 2.0 port, it loses power during the boot process. When booting is complete, it does not experience any sudden power loss / disconnect.
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Re: XU4 persistent power to USB 3 during reboot

Unread postby odroid » Mon Sep 04, 2017 8:11 am

Which USB devices did you test?
Another possible root cause can be a short period of load switch off by over-current protection of USB load switch IC NCP380.
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Re: XU4 persistent power to USB 3 during reboot

Unread postby CalebCarroll » Thu Sep 14, 2017 1:51 am

Going to mark this one as solved. It's not applicable to either the 4.9 kernel nor the XU4 in general. I've identified the cause of the problem as being related to the specific USB device being tested. Any chance someone could move this thread to a different section? This was my first post and I realise now that I should have posted it in "Issues" rather than "4.9 Debugging Party".
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