Hello,
I have a strange problem with embedded system I'm developing on. It is a
board with TI's DM365 SoC. It has 2514b 4-port hub connected to its usb
interface. It is running Linux in version 2.6.37 with TI patches, but I
tried also vanilla and another older or recent versions and the situation
is the same.
An USB GSM model (Telit HE910) is one of the devices connected to the hub,
cdc_acm driver automatically detects it and ttyACM0 - ttyACM6 are created
in dev directory. ttyACM0 and ttyACM3 can be used to send and read AT
commands and both of them alone works as expected. The problem arises when
I try to use them at once.
eg.
cat /dev/ttyACM0 &
cat /dev/ttyACM3
Unfortunately the second command ends with following error:
tty_port_close_start: tty->count = 1 port count = 0.
cat: can't open '/dev/ttyACM3': Input/output error
I have tried to reproduce this behavior directly on my PC, but there it
works like a charm - at first I thought that the problem lies in cdc_acm
driver, but today I tried to desolder the hub and connect the USB modem
directly to the SoC. And voila it works too and I can use both ACM
interfaces at time (one for ppp connection and second for maintenance and
voice commands). But I definetely need a hub there...
Could please someone give me some explanation how and why the 2414b USB
HUB can do such problems and if there is any way how to fix it?
with best regards
Jan
--
Tato zpráva byla vytvořena převratným poštovním klientem Opery:
http://www.opera.com/mail/
--
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
