Hi, I'm starting a new thread with this since my previous one had some unnecessary information/complexity. I'm having issues using an FT232RL device through the ftdi_sio 1.6 driver. After using a particular app to access the device, I have problems communicating with it. I've tried to narrow down the steps that lead to failure. The issue is intermittent -- the problem occurs most of the time, but not always. The problem doesn't occur on another device using a Prolific chipset. I'm using an external application which does a bunch of stuff to try and autodetect the device type. At a glance, I think it tries to change baud rates, data bits/stop bits and flow control. After its done, the application is told to relinquish the device (close it). Here is the relevant output of an strace on the application: http://pastie.org/pastes/3077794/text After the application is closed (process is killed, nothing is accessing the device as verified with lsof), the issue starts... I open the port (ie /dev/ttyUSBx) in any other application and it seems like I can talk TO the device, but not receive anything from it. The device in question will flash LEDs in a particular sequence when a specific command is given, and if I send that command, the LEDs flash as expected. The device should also be giving back some data, but I don't ever see it. At this point, if I disconnect the device, the system will recognize the disconnection (I'll see the message in dmesg) but I won't be able to unload ftdi_sio with modprobe -r, as the system complains it in use. If I try to force it, the command will hang. Eventually (with no further action), I'll get "[ 720.526646] INFO: task khubd:123 blocked for more than 120 seconds" and a call trace from dmesg. After this point I guess whatever major module handles usb (usbcore?) hangs. If I disconnect my mouse for instance, reconnecting it isn't detected and the mouse is no longer accessible until a reboot. The relevant parts of these events in kernel.log with debugging enabled on the module is shown here: http://pastie.org/pastes/3077786/text Here's the output of ftdi_sio loaded with debug arguments for when the issue occurs. I've separated the point in time after using the application whose strace I linked to earlier and removed 'ftdi_process_packet' messages. Regardless of whether the problem happens or not, ftdi_sio's debug output consistently shows that certain ioctl args are not supported... they are: 0x5401 TCGETS 0x5402 TCSETS 0x540b TCFLSH I don't really know what implies. I'm pretty lost with how to try fixing this issue, and would great appreciate any advice. Regards, Preet -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
