Comment 2 for bug 376128

We are using ftdi_sio with a 232M chip.

On intrepid and with jaunty's 2.6.27 kernel, ftdi_sio works like a charm on different setups (x86 IA32 and x86_64).

On 2.6.28-10 and -13, we have the following regression (x86 IA32): one program opens the device, sends/receives data, then closes it. This works at least once. This can be done several times, but at some point it will fail: after a close() (or directly a program exit), no other program can open the device again (Input/output error in open). If I rmmod the module (rmmod or modprobe -r), unplug/plug the device back again, etc. (I tried many combinations) I cannot ever open the device again: I have to reboot the machine. And modprobe with debug=1 doesn't suggest anything (no message beyond USB device connect/enumeration). I didn't spy on the bus with usbmon since I could have a working setup with 2.6.27.

I noticed that the bug seems to be more (always ?) reproducible with pyserial then with direct libc open/close from C: after one has used a pyserial script with the device, nobody can ever use the device again. Reboot needed...