I have a raspberry pi running with about 40 usb devices. There's 4 usb hubs with 10 keys each. I've noticed a problem starts to occur when I start the server with all of the devices connected. The keyboard and mouse are not responsive on the system and I'm unable to ping the Pi.
The system appears to be fine if I start the Pi with 10 devices. Problems start to occur when I turn on and connect 20 or more devices.
Here's the messages I see in the syslog:
Aug 20 14:56:21 raspberrypi vhusbdarmpi3: Device 11243 [088e:5036] BOUND to connection 8
Aug 20 14:56:21 raspberrypi kernel: [ 26.881882] usb 1-126.96.36.199: reset full-speed USB device number 38 using dwc_otg
Aug 20 14:56:21 raspberrypi kernel: [ 27.027418] ERROR::assign_and_init_hc:1408: assign_and_init_hc: Failed to allocate memory to handle non-dword aligned buffer case