As part of our work on Rev 1.3 of the controller we found an unusual "feature" and is was related to a cheap USB hub we are using in one of system test setups. What we found was that this hub didn't turn power off properly when the host laptop released the port as it should. Indirectly this was causing a lockup of the array FPGAs. We have added an extra reset function to clock startup and this appears to solve the issue.
On our test setups we are now getting a good balance of hashing now on both FPGAs running the twin bitstream so I would recommend anyone with a controller on Rev 1.0/1.1 updates it to Rev 1.3.
Yohan,
I've flashed all my boards to 1.3, now I'm getting
[2012-07-12 19:43:44] Icarus Detect: Test failed at /dev/ttyUSB2: get 00000000, should: 000187a2
[2012-07-12 19:43:44] Icarus Detect: Test failed at /dev/ttyUSB3: get 00000000, should: 000187a2
port numbers are nearly random, sometimes it's ttyUSB26/27, sometimes just a FPGA out of a couple like ttyUSB15 right now.
ttyUSB2/3 fail nearly always.
Is the new revision requiring more power from the USB port?
I'm on two usb hubs, a 2.5A 7 port hub and a 2.5A 4 port hub from Belkin for my ten boards.
spiccioli