2005-03-28 16:48:54

by James Lamanna

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Subject: More FTDI 232BM chip issues...

Earlier I posted about having long delay issues when reading back
bytes from a FTDI 232BM USB->Serial chip.
Now, I've noticed that after a long period of time of semi-continual
use (maybe 8+ hours) I see the following messages in my kernel.log:

Mar 24 23:46:42 displaytest kernel: hub 2-0:1.0: port 2 disabled by
hub (EMI?), re-enabling...
Mar 24 23:46:42 displaytest kernel: usb 2-2: USB disconnect, address 4
Mar 24 23:46:42 displaytest kernel: ftdi_sio 2-2:1.0: device disconnected
Mar 24 23:46:42 displaytest kernel: usb 2-2: new full speed USB device
using address 5
Mar 24 23:46:42 displaytest kernel: ftdi_sio 2-2:1.0: FTDI FT232BM
Compatible converter detected
Mar 24 23:46:42 displaytest kernel: usb 2-2: FTDI FT232BM Compatible
converter now attached to ttyUSB1

Of course I have a test program running overnight and when the device
comes back up it switches device names (because my test program has
the port still open), which causes it to die at that point.

Is there any particular reason the hub would disable that port? Or am
I in flakey hardware land here?

Thanks.

-- James Lamanna