Problem in reading through USB Serial - Jan Axelson Program

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1

Hello Jan, Vladimir, Ben and all ....

I have taken the program on the link below
as suggested by Jan on this forum ...for using usb as uart on
BeagleBoard xm and interfaced with the windows PC.

http://www.lvr.com/code/usb_serial_port.c

I have connected BeagleBoard uart to windows hyperterminal and its
connected successfully .

Now writing from BeagleBoard to Windows Hyperterminal is done
comfortably but but as i read on Beagleboard ..i.e write something on
Hyperterminal ..at once

These ERROR MESSAGES come on the BB side. Please help as I am stuck.

Thanks and Regards,

Mohit

[ 236.729919] musb g_serial gadget disconnected.
[ 238.990112] g_serial gadget: high speed config #2: CDC ACM config
[ 274.613616] ------------[ cut here ]------------
[ 274.618286] WARNING: at kernel/mutex.c:207 __mutex_lock_slowpath
+0x6c/0x278()
[ 274.625488] Modules linked in: g_serial rfcomm ipv6 hidp l2cap
bluetooth rfkill
[ 274.632965] [<c0040c40>] (unwind_backtrace+0x0/0xdc) from
[<c006cdb4>] (warn_slowpath_common+0x4c/0x80)
[ 274.642425] [<c006cdb4>] (warn_slowpath_common+0x4c/0x80) from
[<c04852a0>] (__mutex_lock_slowpath+0x6c/0x278)
[ 274.652496] [<c04852a0>] (__mutex_lock_slowpath+0x6c/0x278) from
[<c04854b8>] (mutex_lock+0xc/0x1c)
[ 274.661621] [<c04854b8>] (mutex_lock+0xc/0x1c) from [<c029c014>]
(echo_set_canon_col+0x18/0x40)
[ 274.670379] [<c029c014>] (echo_set_canon_col+0x18/0x40) from
[<c029e4d8>] (n_tty_receive_buf+0xc54/0xf38)
[ 274.680023] [<c029e4d8>] (n_tty_receive_buf+0xc54/0xf38) from
[<c02a0c70>] (flush_to_ldisc+0x114/0x1e0)
[ 274.689514] [<c02a0c70>] (flush_to_ldisc+0x114/0x1e0) from
[<bf09ce3c>] (gs_rx_push+0x140/0x220 [g_serial])
[ 274.699340] [<bf09ce3c>] (gs_rx_push+0x140/0x220 [g_serial]) from
[<c0072e00>] (tasklet_action+0x74/0xbc)
[ 274.708984] [<c0072e00>] (tasklet_action+0x74/0xbc) from
[<c0073400>] (__do_softirq+0xe8/0x1f0)
[ 274.717742] [<c0073400>] (__do_softirq+0xe8/0x1f0) from
[<c007354c>] (irq_exit+0x44/0x98)
[ 274.725982] [<c007354c>] (irq_exit+0x44/0x98) from [<c003b078>]
(asm_do_IRQ+0x78/0x98)
[ 274.733947] [<c003b078>] (asm_do_IRQ+0x78/0x98) from [<c003bd40>]
(__irq_usr+0x40/0xa0)
[ 274.742004] Exception stack(0xdfbabfb0 to 0xdfbabff8)
[ 274.747100] bfa0: 00000000
be9bbcdd 0000000a 00000003
[ 274.755340] bfc0: 40020000 00000000 00008588 00000003 00000000
00000000 40025000 be9bbccc
[ 274.763580] bfe0: 00000000 be9bbcb8 000089f0 400da29c 60000010
ffffffff
[ 274.770233] ---[ end trace c191d2c1d7b00f1e ]---

2

Hi,

Test whether this code is working? Also be careful about the bps you set in BB(using C code)… The attached code has 115200…

Bye

serialtestv1.0.c (1.55 KB)

3

Hi Arun,
Could you please tell me , which kernel version , have you tried this successfully on ?

as it seems its a problem in some kernel version…!!

Thanks
Nidhi

4

hi Arun,

we tried ur program…

we have BB on one side and Windows on other connected through usb gadget serial.

we first do modprobe g_serial

and then run ur program by using ./executable /dev/ttyGS0 command

the following are the results:

1))program seems to catch q as it exits on pressing q

2)but any other character not being printed on BB cmd prompt …as program says it should.

3)we tried replacing macro STDOUT_FILENO with 2 but no result. again nothing is being typed from key board to BB cmd prompt…

4)we tried with printf after read from Windows :

while (c!=‘q’)
{
if (read(tty_fd,&c,1)>0)
{
printf(“i have got %c”,c);
fflush(stdout);
fflush(stdin);
return 0;
}
}

It pressed 'k ’ on HT on windows and i got the following result:

root@beagleboard:~# ./serialtestv3 /dev/ttyGS0
^Z�
and the program exited.

nothing worked
please help

Regards

Mohit