Bug#833918: linux: Please enable cdc_ncm and cdc_mbim in d-i to support 'Dell 4-in-1 Adapter' Ethernet

[Bjørn Mork]

John Paul Adrian Glaubitz  writes:

> This adapter uses the cdc_ncm/cdc_mbim kernel modules which are currently 
> being disabled for
> debian-installer as those were suspected to be used by modems only [2], which 
> is not the
> case, however.

cdc_mbim is modem-only. cdc_ncm is not.

The reason you see cdc_mbim loaded is because of an oddity in the MBIM
spec, allowing an USB interface to be both NCM and MBIM depening on the
active altsetting. The cdc_mbim driver is therefore matching NCM
interfaces to be able to detect this sort of dual function.  But that's
completely irrelevant to your ethernet adapter.  MBIM cannot be used on
an ethernet (it has no no L2 headers).

By avoiding cdc_mbim, you can also drop the cdc_wdm dependency.


> [ 9105.605635] cdc_ncm 2-1.1:1.5: MAC-Address: 9c:eb:e8:20:f5:5b
> [ 9105.605640] cdc_ncm 2-1.1:1.5: setting rx_max = 16384
> [ 9105.605743] cdc_ncm 2-1.1:1.5: setting tx_max = 16384
> [ 9105.605991] cdc_ncm 2-1.1:1.5 usb0: register 'cdc_ncm' at 
> usb-:00:14.0-1.1, CDC NCM, 9c:eb:e8:20:f5:5b
> [ 9105.680400] cdc_ncm 2-1.1:1.5 enx9cebe820f55b: renamed from usb0

See?  This is only using cdc_ncm and will work fine even if cdc_mbim is 
unavailable.


Bjørn

Bug#833918: linux: Please enable cdc_ncm and cdc_mbim in d-i to support 'Dell 4-in-1 Adapter' Ethernet

[John Paul Adrian Glaubitz]

Source: linux
Version: 4.6.4-1
Severity: normal

Hi!

While reinstalling my Dell XPS-13 9343 yesterday, I ran into the problem that 
the Ethernet
adapter in my external 'Dell 4-in-1 Adapter' [1] was not detected. This adapter 
is necessary
because the XPS ultrabook series do not have an internal Ethernet adapter but 
require an
external USB Ethernet adapter, with the 4-in-1 adapter from Dell being the 
standard
accessory.

This adapter uses the cdc_ncm/cdc_mbim kernel modules which are currently being 
disabled for
debian-installer as those were suspected to be used by modems only [2], which 
is not the
case, however.

Here's the relevant output of lsusb, lsmod and dmesg after attaching the 
adapter my XPS-13
after installing with d-i Alpha 7 with a workaround. After plugging the adapter 
in, no
additional configuration is necessary. The Ethernet adapter just works out of 
the box
and we should therefore enable these modules in d-i, I think.

glaubitz@ikarus:~$ lsusb |grep Bus\ 002
Bus 002 Device 005: ID 17e9:436f DisplayLink
Bus 002 Device 004: ID 2109:0210 VIA Labs, Inc.
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
glaubitz@ikarus:~$ lsmod |grep cdc
cdc_mbim   16384  0
cdc_wdm20480  1 cdc_mbim
cdc_ncm32768  1 cdc_mbim
cdc_ether  16384  0
usbnet 40960  3 cdc_mbim,cdc_ncm,cdc_ether
usbcore   241664  14 
btusb,snd_usb_audio,uvcvideo,snd_usbmidi_lib,ehci_hcd,ehci_pci,usbhid,usbnet,cdc_mbim,cdc_ncm,cdc_wdm,xhci_hcd,xhci_pci,cdc_ether
glaubitz@ikarus:~$ dmesg | tail -n30
[ 9104.050604] usb 2-1: new SuperSpeed USB device number 4 using xhci_hcd
[ 9104.06] usb 2-1: New USB device found, idVendor=2109, idProduct=0210
[ 9104.067782] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 9104.067785] usb 2-1: Product: USB3.0 Hub
[ 9104.067786] usb 2-1: Manufacturer: VIA Labs, Inc.
[ 9104.069404] hub 2-1:1.0: USB hub found
[ 9104.069854] hub 2-1:1.0: 1 port detected
[ 9104.178489] usb 1-1: new high-speed USB device number 11 using xhci_hcd
[ 9104.511724] usb 1-1: New USB device found, idVendor=2109, idProduct=2210
[ 9104.511731] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 9104.511734] usb 1-1: Product: USB2.0 Hub
[ 9104.511736] usb 1-1: Manufacturer: VIA Labs, Inc.
[ 9104.512978] hub 1-1:1.0: USB hub found
[ 9104.514078] hub 1-1:1.0: 4 ports detected
[ 9105.578571] usb 2-1.1: new SuperSpeed USB device number 5 using xhci_hcd
[ 9105.595153] usb 2-1.1: New USB device found, idVendor=17e9, idProduct=436f
[ 9105.595157] usb 2-1.1: New USB device strings: Mfr=1, Product=2, 
SerialNumber=3
[ 9105.595160] usb 2-1.1: Product: Dell 4-in-1 Adapter
[ 9105.595162] usb 2-1.1: Manufacturer: DisplayLink
[ 9105.595164] usb 2-1.1: SerialNumber: 1505140265
[ 9105.602515] usb 2-1.1: Warning! Unlikely big volume range (=511), cval->res 
is probably wrong.
[ 9105.602522] usb 2-1.1: [14] FU [Dell USB Audio Playback Volume] ch = 6, val 
= -8176/0/16
[ 9105.605635] cdc_ncm 2-1.1:1.5: MAC-Address: 9c:eb:e8:20:f5:5b
[ 9105.605640] cdc_ncm 2-1.1:1.5: setting rx_max = 16384
[ 9105.605743] cdc_ncm 2-1.1:1.5: setting tx_max = 16384
[ 9105.605991] cdc_ncm 2-1.1:1.5 usb0: register 'cdc_ncm' at 
usb-:00:14.0-1.1, CDC NCM, 9c:eb:e8:20:f5:5b
[ 9105.680400] cdc_ncm 2-1.1:1.5 enx9cebe820f55b: renamed from usb0
[ 9105.757799] IPv6: ADDRCONF(NETDEV_UP): enx9cebe820f55b: link is not ready
[ 9105.757884] IPv6: ADDRCONF(NETDEV_UP): enx9cebe820f55b: link is not ready
[ 9108.770155] cdc_ncm 2-1.1:1.5 enx9cebe820f55b: network connection: 
disconnected
glaubitz@ikarus:~$

Thanks,
Adrian

> [1] 
> http://accessories.us.dell.com/sna/productdetail.aspx?c=us=19=en=470-ABHH
> [2] 
> https://anonscm.debian.org/cgit/kernel/linux.git/tree/debian/installer/modules/nic-usb-modules

--
 .''`.  John Paul Adrian Glaubitz
 : :' :  Debian Developer - glaub...@debian.org
 `. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
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