Topic: USB 2.0 port not playing nice with USB 1.1 device: dual serial adapter
I'm currently struggling with, what appears to be, a driver problem when I attempt to connect a Manhattan Dual USB to Serial adapter to the Chumby One. The converter is a USB 1.1 device.
This works like a champ on the Chumby Classic.
When I connect the adapter and restart the chumby one, both Serial ports appear to be recognized ( /dev/ttyUSB0 and /dev/ttyUSB1 ).
However, when I attempt to access the second of the two devices (in either order), I get the following system error:
pl2303 ttyUSB0: pl2303_open - failed submitting interrupt urb, error -28
This gets reported to my unix process as "Protocol Error", and the port fails to work from that point on.
The requisite ftdi_sio driver is loaded properly and I've prevented getty from spawning a shell on ttyUSB0.
Searching for this same error message, I found another poor soul who was experiencing the EXACT same problem, but on a linux server:
http://lkml.indiana.edu/hypermail/linux … 00546.html
The solution to his problem was to configure the 2.0 port to behave like a 1.1 port using the following: echo 1 > /sys/class/usb_host/usb_host1/companion
Desperate as I am, I tried this and... not surprisingly, it locked up everything having to do with USB.
It was implied in the linked thread that my problem is a symptom of the usb 1.1 device simply not being able to respond to interrupts fast enough.
I've tried resetting the USB hardware ( reset_usb.sh ) and restarting networking, but this merely clears the error. When I connect to the second port ( regardless of the order in which I connect to them ), the error recurs.
Any thoughts or suggestions?
-Sean