Re: bugreport: huawei_cdc_ncm control device freezes for 3-5 minutes on connect with E3276 LTE modem

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Oct 3, 2014 at 10:01 AM, Erik Alapää <erik.alapaa@xxxxxxxxx> wrote:
> Problem: When connecting to a Huawei E3276 LTE modem using
> 'AT+CGACT=1,1' in minicom over /dev/cdc-wdm1, the cdc-wdm device
> freezes for 3-5 minutes until accepting AT commands again.
>
> Keywords: huawei_cdc_ncm, LTE, AT commands, cdc-wdm
>
> Detailed problem description:
>
> I am using a 4G mobile USB dongle with the huawei_cdc_ncm driver in
> Linux kernel 3.16. In general, the driver works well, but one major
> issue is that bringing the modem up using 'AT+CGACT=1.1' freezes the
> /dev/cdc-wdm1 control device for 3-5 minutes. After that, the device
> accepts more commands over minicom. Note that I do get connectivity,
> directly after the CGACT I can get a DHCP address for wwan0 and the
> bandwidth is approx 20 Mbit/s downstream and 6 Mbit/s upstream.
>
> I have tried building a custom 3.16 kernel with a few printk:s in
> cdc_ncm.c and huawei_cdc_ncm.c, but found nothing suspicious.
>
> Kernel version (from /proc/version): 3.16
> Environment: Thinkpad L440 64-bit x86 (Intel Core i5-4200M cpu) laptop
> with Kubuntu 14.04.1 LTS
> Kernel modules: huawei_cdc_ncm,cdc_ncm
>
> Workaround: Bring up the device with
> AT^NDISDUP=1,1,"internet.telenor.se" instead. Also worth noting is
> that AT+CGACT=1,1 does not freeze the control connection if using
> /dev/ttyUSB0.


Regardless of the actual issue in the kernel driver, if any, NDISDUP
in the cdc-wdm device is the way to go to connect that modem.

-- 
Aleksander
https://aleksander.es
--
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




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux