On 11/07/2013 02:41 AM, Oliver Neukum wrote:
On Tue, 2013-11-05 at 21:16 +0000, Luke-Jr wrote:
I am trying to interface with the "HEX" devices sold by http://technobit.eu/
which appear as CDC-ACM devices, but give an I/O error whenever I try to open
them, with some rather unclear error description in dmesg:
[10526714.860052] usb 5-2: new full-speed USB device number 4 using uhci_hcd
[10526715.055017] usb 5-2: New USB device found, idVendor=04d8, idProduct=000a
[10526715.055026] usb 5-2: New USB device strings: Mfr=1, Product=2,
SerialNumber=0
[10526715.055032] usb 5-2: Product: CDC RS-232 Emulation Demo
[10526715.055037] usb 5-2: Manufacturer: Microchip Technology Inc.
[10526715.058200] cdc_acm 5-2:1.0: This device cannot do calls on its own. It
is not a modem.
[10526715.061222] cdc_acm 5-2:1.0: ttyACM0: USB ACM device
[10526756.939797] tty_port_close_start: tty->count = 1 port count = 0.
The manufacturer reports that it works fine on Windows.
Any ideas how I can get this to work on Linux, or at least get more meaningful
error information so it can be debugged further?
What does strace say? The kernel message is a warning, not a hard error.
Also, what are you trying to open it with?
04da:000a is a Microchip demo (as evidenced by the product string) from
their MLA. I just ran it up on a dev board and get the same warning in
the log but can open it (minicom -D /dev/ttyACM0) wth no problem.
Is it maybe a permissions issue?
ls -la /dev/ttyACM*
You didn't give much detail on what error you're getting in userspace.
Alan.
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