Bug 39952

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Mon, 25 Jul 2011 00:05:48 GMT
bugzilla-daemon@bugzilla.kernel.org wrote:

> https://bugzilla.kernel.org/show_bug.cgi?id=39952
> 
>            Summary: LG VL600 4G USB modem broken in 2.6.39
>            Product: Drivers
>            Version: 2.5
>     Kernel Version: 2.6.39
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: USB
>         AssignedTo: greg@kroah.com
>         ReportedBy: prox@prolixium.com
>         Regression: Yes
> 
> 
> Hi - 
> 
> It appears that upon inclusion into 2.6.39 mainline, the driver for the LG
> VL600 has stopped working.  The original patch for 2.6.38 can be obtained
> below:
> 
>
> https://github.com/balrog-kun/LG-VL600-utils/blob/master/lg-vl600-linux-2.6.38.patch
> 
> When patched against 2.6.38, this modem works as expected on Verizon's LTE
> network in the USA.  However, ever since it was included in 2.6.39 mainline,
> it
> does not work correctly.  The interface comes up correctly, but no traffic
> passes through the interface, including DHCP request packets.  This has been
> reproduced on both i386 and x86-64.
> 
> After looking into this, I managed to make it work again by doing the
> following:
> 
> --- linux-2.6.39-orig/drivers/net/usb/cdc_ether.c 2011-07-24
> 19:48:36.000000000
> -0400
> +++ linux-2.6.39/drivers/net/usb/cdc_ether.c 2011-07-24 19:49:27.000000000
> -0400
> @@ -567,7 +567,7 @@
>  {
>      USB_DEVICE_AND_INTERFACE_INFO(0x1004, 0x61aa, USB_CLASS_COMM,
>                USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE),
> -    .driver_info = (unsigned long)&wwan_info,
> +    .driver_info = 0,
>  },
> 
>  /*
> 
> Apparently with wwan_info being set, the lg-vl600 driver was no longer being
> registered correctly, and the modem is seen as a generic cdc_ether device:
> 
> [   19.462567] usb 1-1: Product: LG UDC-AHB Subsystem
> [   19.476948] usb 1-1: Manufacturer: LG ELECTRONICSInc
> [   19.646303] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
> [   19.726490] usbcore: registered new interface driver cdc_acm
> [   19.743535] cdc_acm: v0.26:USB Abstract Control Model driver for USB
> modems
> and ISDN adapters
> [   19.826110] cdc_ether 1-1:1.0: wwan0: register 'cdc_ether' at
> usb-0000:00:0f.5-1, Mobile Broadband Network Device, 64:99:5d:f7:c0:64 
> 
> With it set back to 0, the driver is correctly registered:
> 
> [   19.667135] usb 1-1: Product: LG UDC-AHB Subsystem
> [   19.681527] usb 1-1: Manufacturer: LG ELECTRONICSInc
> [   19.908204] cdc_acm 1-1:1.2: ttyACM0: USB ACM device
> [   19.926913] usbcore: registered new interface driver cdc_acm
> [   19.943957] cdc_acm: v0.26:USB Abstract Control Model driver for USB
> modems
> and ISDN adapters
> [   20.056480] usbcore: registered new interface driver cdc_ether
> [   20.142189] lg-vl600 1-1:1.0: eth3: register 'lg-vl600' at
> usb-0000:00:0f.5-1, LG VL600 modem, 64:99:5d:f7:c0:64
> 
> This regresses the fix to name the device wwanX instead of ethX, so there's
> probably a better way of doing this.
> 
> Let me know what other information may be useful.
>

A patch referencing this bug report has been merged in Linux v3.2-rc3:

commit 6d74eb9442fb113c97edc88a1c658462db711337
Author: Mark Kamichoff <prox@prolixium.com>
Date:   Wed Nov 9 11:48:10 2011 +0000

    net/usb: Misc. fixes for the LG-VL600 LTE USB modem

All USB bugs should be sent to the linux-usb@vger.kernel.org mailing 
list, and not entered into bugzilla.  Please bring this issue up there,
if it is still a problem in the latest kernel release.

Let's assume it's fixed by the patch above.