Rock64 usb2.0 Power Control Floating GPIO Tutorial Files & Notes

[MarkHaysHarris777]

It worked fine for me here on xenial-mate-rock64-0.4.16-83-arm64.

Thank you KnReLe !   


I too have tested now on both xenial-minimal, and xenial-mate.  Both worked, gpio2 is set and held low, and the usb2.0 can be power cycled.

Caveat:  depending on timing ( when the user logs on vs how long it takes for rc.local to run ) there may be a very brief second or two where the usb 5v power drops before the automation pulls the gpio2 low turning on the usb power regulators.  If this happens to you , please let me know , and let me know how frequent this occurs (PM me, or send a private message, or stop by the irc).  Typically this is going to occur if the user does the logon from the gui before  the boot process has completed;  in other words, this will likely not occur if the user waits until the boot-up is complete before logging on.  This is something that can be seen while monitoring the serial console, for instance.  So, if the user waits a few seconds to logon after boot to give the boot process time to complete fully (serial console is at a logon prompt) it is unlikely that this caveat will occur.

Please review the entire tutorial , and notice that we're enabling the service in systemd 'earlier' which eliminates the timing problem with the legacy rc.local;  so I removed the rc.local step.


Thanks