EM7455 does not enumerate after at!reset

IoT Modules MC/EM Series
1

I have a EM7455 module running on my embedded Linux ARM board. I noticed that sometimes after doing a AT!RESET on the module, the module does not enumerate again after reset. Doing a dmesg on my Linux prompt, I see:

dmesg

GobiSerial driver ttyUSB2: GobiSerial converter now disconnected from ttyUSB2
Send ZERO CONF FAIL!
GobiSerial 4-1:1.0: device disconnected
GobiSerial driver ttyUSB1: GobiSerial converter now disconnected from ttyUSB1
GobiSerial 4-1:1.2: device disconnected
GobiSerial driver ttyUSB0: GobiSerial converter now disconnected from ttyUSB0
GobiSerial 4-1:1.3: device disconnected
GobiNet 4-1:1.8: eth3: unregister ‘GobiNet’ usb-0002:04:00.0-1, GobiNet Ethernet Device
xhci_hcd 0002:04:00.0: xHCI host not responding to stop endpoint command.
xhci_hcd 0002:04:00.0: Assuming host is dying, halting host.
xhci_hcd 0002:04:00.0: HC died; cleaning up
usb 4-1: USB disconnect, device number 2

Anyone know what is going on? Is my USB host driver dead?
I am running Linux 3.6.5.

Thanks

2

@dchou4u,

This is probably going to be something with the USB hub, the firmware on the MC will enumerate the same time whenever it sees a host system and the USB hub on the host system will see a given device’s VID/PID when it tried to enumerate and from this the host system will know to use/invoke the driver for the given VID/PID.

Regards

Matt

3

Thanks for the reply.

Is there a way for me to release the GobiNet and GobiSerial devices after issuing the AT!RESET command? Perhaps this allows the host to orderly release the devices without the sudden shock of handling the disappearance of the modem.