[Bug 658574] [NEW] FT2232 FTDI kernel bug serial port access wrong

[Brian]

Public bug reported:

Starting with 2.6.32-25, my JTAG based on FT2232 no longer functions
normally.

ttyUSBx device now appears to be data from FIFO/JTAG port rather than
normal USART as per 2.6.32-21, 2.6.32-24 releases (i386).

I suspect some change introduced in the ftdi driver in the kernel. Bug #
655868 may be related as it is also FTDI module with same releases
broken and not working, but behavior is distinct.

Specifically, these are the behaviors:
On boot there are two ttyUSBx devices. ttyUSB0 and ttyUSB1. 

I have a udev rule to add these:
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bcda", RUN+="/sbin/modprobe -q ftdi-sio product=0xbcda vendor=0x0403"

On running openOCD (for the JTAG) ttyUSB0 is disconnected (I don't know
what this device ever is I assume it is the FIFO).

Attaching to ttyUSB1 (terminal) during openOCD results in what appears
the be the polling data of the FIFO (other endpoint in the compound
device) on ttyUSB1. Proper behavior is USART data. This behavior started
with kernel 2.6.32-25, reversion to 2.6.32-24 resolves the issue.
(ttyUSB0 is still disconnected as described but ttyUSB1 has the correct
data stream on it).

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

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FT2232 FTDI kernel bug serial port access wrong
https://bugs.launchpad.net/bugs/658574
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