Quick test of Asus USB-N10 WiFi adapter under Linux

Asus USB-N10 known also as ASUS EZ N is a WiFi b/g/n USB adapter. It's sized between common mini adapters and long classical ones. Slightly longer housing was used to put bigger antenna than that found in mini adapters. How this Realtek based WiFi adapter works under Linux? Lets find out.

Asus N10 WiFi adapter

The WiFi adapter is based on Realtk RTL8188S chipset and uses r8712u Kernel driver that is available from some time. Asus gives Kernel 2.6 as the minimal supported version, however it's good to have the latest Kernel for Your distribution. There are few or more reviews of this card from other users. It worked out of the box and it even works on Raspberry Pi with up-to-date Raspbian distribution (or other with recent Kernel).

When connected we should see some log entries in dmesg, like those:
usb 2-1.1: new high-speed USB device number 5 using ehci-pci
usb 2-1.1: New USB device found, idVendor=0b05, idProduct=1786
usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1.1: Product: ASUS EZ N Network Adapter
usb 2-1.1: Manufacturer: Manufacturer Realtek 
r8712u: module is from the staging directory, the quality is unknown, you have been warned.
r8712u: Staging version
r8712u: register rtl8712_netdev_ops to netdev_ops
usb 2-1.1: r8712u: USB_SPEED_HIGH with 4 endpoints
usb 2-1.1: r8712u: Boot from EFUSE: Autoload OK
usb 2-1.1: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
usbcore: registered new interface driver r8712u
r8712u 2-1.1:1.0 wlan2: 1 RCR=0x153f00e
r8712u 2-1.1:1.0 wlan2: 2 RCR=0x553f00e
lsusb will return:
ID 0b05:1786 ASUSTek Computer, Inc. USB-N10 802.11n Network Adapter [Realtek RTL8188SU]

Aside of the Kernel driver a firmware file is also loaded - /lib/firmware/rtlwifi/rtl8712u.bin. This will should be present in nearly any modern distribution (except those minimalistic or non-desktop oriented). If the firmware file is missing then dmesg logs will tell you that and the card won't work.

When connecting this (or other) adapter to a laptop which already has the internal WiFi adapter working it's good to disconnect from access point (if used). You can also disable the internal WiFi adapter with a switch on the laptop housing if it's available.

If you connect a USB WiFi adapter as a second one then NetworkManager (or other apps?) will list two devices and for every of them it will list access points given card found. You may get quite technical WiFi card names on that list so be prepared...

How it worked?

The not-smallest-possible antenna did gave quite stable performance during in-house test usage. The reported signal of few access points was slightly better on my Asus N53S than the internal Atheros card got (but only slightly). Card owner is using it currently (few weeks at least at the moment of writing) and has no issues under Ubuntu 13.04. I tested it on two laptops and one PC under Ubuntu 13.04 (and partially also on 12.10) and it did work out of the box (with a "small" problem described below).

This card works, it's quite good performer, it's quite small although not mini-sized (do you need such size?). It's good for Raspberry and probably for other ARM-based mini computers. It's also good if your laptop or PC needs a working WiFi adapter. It's rather not the weapon of choice when you have a weak signal or some walls the signal has problem penetrating (for that you need something with bigger external antenna or also better router, signal repeaters).

Encountered problems

Asus WiFi adapter did make some problems when connected to an... Asus N53S laptop (it did work with newer Asus ultrabook). When connected the dmesg log showed entries like:

usb 2-1.2: new low-speed USB device number 12 using ehci_hcd
usb 2-1.2: device descriptor read/64, error -32
usb 2-1.2: device descriptor read/64, error -32
The card wasn't working and few times when plugging in/out it crashed the whole system. When reporting the problem on Ubuntu launchpad I was pointed to packaged upstream Kernels and I tested one of RC versions of 3.9 Kernel. This version solved the problem. On Asus N53S the WiFi adapter did not work on older Kernels (3.8 in Raring Ringtail and older in Ubuntu 12.10). It did work under 3.9. What's funny is that the newer Asus (and another Samsung) ultrabook had no problems with this card on 3.8 Kernel. I'm assuming it's a rare problem with the motherboard or USB or motherboard controller + that WiFi chipset/driver. If the problem was more common it would showed up in someones review.

When the WiFi was working the driver pointed out that it's still something new and... you have been warned.

r8712u: module is from the staging directory, the quality is unknown, you have been warned.
r8712u: DriverVersion: v7_0.20100831

Either so the WiFi dongle worked as designed under Linux.


Linux and programming, 22 May 2013

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