On Sat, 2012-08-18 at 09:14 +0200, Mathieu MD wrote: [...] > I control a four relays board throught an USB cable connected to a > Xen Dom0 running Debian 6.0.5. > > It works great: I can switch on and off the relays through some "echo" > into /dev/ttyUSB0 (echo -e "\xff\x01\x01" > /dev/ttyUSB0). > > I added a crontab to send such echo every 15 minutes. It works great at > the begining. > > But after some hours, I get this error message in /var/log/syslog each time I "echo" to ttyUSB0: > #---------------------8<----------------------8<---------------------- > Aug 18 09:04:32 zen kernel: [1677762.865609] ftdi_sio ttyUSB0: Unable to write latency timer: -62 > Aug 18 09:04:32 zen kernel: [1677762.869623] ftdi_sio ttyUSB0: ftdi_set_termios FAILED to set databits/stopbits/parity > Aug 18 09:04:32 zen kernel: [1677762.871604] ftdi_sio ttyUSB0: ftdi_set_termios urb failed to set baudrate > Aug 18 09:04:32 zen kernel: [1677762.875622] ftdi_sio ttyUSB0: urb failed to clear flow control > Aug 18 09:04:32 zen kernel: [1677762.879604] ftdi_sio ttyUSB0: urb failed to clear flow control > Aug 18 09:04:32 zen kernel: [1677762.881620] ftdi_sio ttyUSB0: error from flowcontrol urb > Aug 18 09:04:32 zen kernel: [1677762.885623] ftdi_sio ttyUSB0: Unable to write latency timer: -62 > Aug 18 09:04:32 zen kernel: [1677762.889637] ftdi_sio ttyUSB0: ftdi_set_termios FAILED to set databits/stopbits/parity > Aug 18 09:04:32 zen kernel: [1677762.891622] ftdi_sio ttyUSB0: ftdi_set_termios urb failed to set baudrate > Aug 18 09:04:32 zen kernel: [1677762.895616] ftdi_sio ttyUSB0: urb failed to clear flow control > Aug 18 09:04:32 zen kernel: [1677762.903189] ftdi_sio ttyUSB0: error from flowcontrol urb > #---------------------8<----------------------8<---------------------- > > I have to unplug the USB cable and plug it back to get it to work again. Is this a regression from an earlier version of Debian or the Linux kernel package? [...] > The first times I echo to ttyUSB0 after plugin it, the log shows this: > #---------------------8<----------------------8<---------------------- > Aug 18 09:09:36 zen kernel: [1678067.020400] hub 3-0:1.0: port 3 disabled by hub (EMI?), re-enabling... > Aug 18 09:09:36 zen kernel: [1678067.020439] usb 3-3: USB disconnect, address 21 > Aug 18 09:09:36 zen kernel: [1678067.020793] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0 > Aug 18 09:09:36 zen kernel: [1678067.020839] ftdi_sio 3-3:1.0: device disconnected [...] Is there actually a hub between the computer's USB port and the serial device? If so, does plugging the device in directly make a difference? Ben. -- Ben Hutchings I say we take off; nuke the site from orbit. It's the only way to be sure.
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