I have Ubuntu running on a Mac Mini with adb 1.0.31. I am trying to attach 3 devices directly and four devices via a powered hub. Every time devices attached start to fluctuate on adb after some time. For example I would see all the devices attached initially but within a few minutes last 2-3 devices will come and go on adb every now and then. Eventually more will behave same way.
I checked on dmesg and found this:
[ 1001.384481] xhci_hcd 0000:00:14.0: Not enough host resources, active endpoint contexts = 60 [ 1001.384495] hub 3-4.4:1.0: couldn't allocate port 4 usb_device
I have tried Fedora on Mac mini as well and I am seeing the same issue. I have tried on 4 different Mac Minis as well.