Hi Greg,
On May 17 2007 05:45, Greg KH wrote:
>>
>> I seem to have problems with the ark3116 driver from 2.6.18.8. This
>> is a USB-RS232 cable. Just opening the /dev/ttyUSB0 device gives
>> (this is the debug output enabled by `modprobe ark3116 debug=1`).
>>
>> The lines that look suspicious are
>> /serial/ark3116.c: 124 < 1 bytes [0xFFFFFFB0]
>> and
>> /serial/ark3116.c: ark3116_ioctl cmd 0x5401 not supported
>
>Why is this suspicious? We don't support all ioctls for all usb-serial
>drivers, perhaps this one is just not really needed?
ark3116 supports set_termios (0x5402), but does not get_termios
(0x5401). Not sure how that affects userspace, though.
The 0xFFFFFFB0 looks like a simple formatting error (ark3116.c line 66)
an explicit cast to (unsigned char)buf[0] or (unsigned int) seems
required.
>> I have also seen things like "id here < -62 [0x10]", which would
>> indicate that usb_control_msg() returned something very negative
>> (-ETIME!?).
The -62 only shows up when the cable is already connected when I
modprobe ark3116. Reinserting it - and no "-62" shows up.
Maybe this is something normal with USB?
>But does the driver seem to work properly?
>
>> Issuing a write() on an open fd to ttyUSB does not generate any further
>> debug output. Is the driver even complete/functional?
(I found that I already need to modprobe usbserial with debug=1,
since ark3116 uses usb_serial_generic_write)
>Do you get data through the device properly?
I would have to test with a real serial port. (I do not
have any real port right now, just two cables + adapters.)
What certainly does not work: Connecting two cables to each other, that is,
USB-RS232-GenderChanger-RS232-USB. (1) USB ends connected to the same machine
(2) USB ends connected to different machines. Both (1) and (2) do not work.
The write() seems to succeed, but read() blocks:
# klogconsole -l8 -r0
# ./sertest
[...]
Writing...
drivers/usb/serial/usb-serial.c: serial_write_room - port 0
drivers/usb/serial/generic.c: usb_serial_generic_write_room - port 0
drivers/usb/serial/generic.c: usb_serial_generic_write_room - returns 64
drivers/usb/serial/usb-serial.c: serial_write - port 0, 3 byte(s)
drivers/usb/serial/generic.c: usb_serial_generic_write - port 0
ark3116 ttyUSB0: usb_serial_generic_write - length = 3, data = 66 6f 6f
drivers/usb/serial/generic.c: usb_serial_generic_write_bulk_callback -
port 0
drivers/usb/serial/usb-serial.c: usb_serial_port_work - port 0
Reading...
(stops)
Source:
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(void)
{
char bar[4] = {};
int s0 = open("/dev/ttyUSB0", O_RDWR);
int s1 = open("/dev/ttyUSB1", O_RDWR);
if (s0 < 0 || s1 < 0)
abort();
printf("Writing...\n");
write(s0, "foo", 3);
printf("Reading...\n");
read(s1, bar, 3);
printf("Read: %s\n", bar);
return 0;
}
Jan
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