ODROID-C1/-C2 USB Detection only triggered by some devices

[Alan Stern]

On Sun, Jun 27, 2021 at 09:24:45PM -0400, Matt Corallo wrote:
> 
> 
> On 6/27/21 21:16, Alan Stern wrote:
> > You mean that only devices in the first group are affected by this bug?
> > Devices in the second group are always detected correctly regardless of
> > what else is plugged in?  (This contradicts what you wrote above.)
> 
> 
> Correct. Ignoring hotplug (ie on fresh boot or lsusb -vvv), the devices in
> the second group work great. The devices in the first group do too, but only
> if a device from the second group is present.

Okay.  You can try collecting some usbmon traces to see what's going on.  

First test: Boot with nothing plugged in, start a usbmon trace for bus 0 
(cat /sys/kernel/debug/usb/usbmon/0u >mon1.txt), plug in a first-group 
device, run lsusb -v to trigger enumeration, and then kill the "cat" 
process.

Second test: Same as the first except that you boot with a second-group 
device already plugged in.

The differences between the two traces may indicate where the problem 
is.

Alan Stern