How to Use dmesg to Examine Your Wireless Hardware on Android

Introduction

In this tip, you will learn how to discern what wireless chipset your device is using with dmesg. This tip is intended for the Wildcard category.

Sometimes, you will need to import a repository or object file which applies to a specific piece of hardware on your device, and sometimes, you won't even have access to the name of that piece of hardware.

In this case, the closest to a universal means to discern what this hardware is to use dmesg, the driver messaging system. In order to do this, you will need to connect to the device via "adb shell" or use the Terminal Emulator or ConnectBot App, both of which are available in F-Droid and the Google Play Store.

Installing a Terminal Emulator

To use dmesg, you will need to have access to a Terminal Emulator on the device. If you want, you can use "adb shell", but if not you can install a Terminal Emulator on the device. There are two Free Software options available.

Which One?

Well, it depends. It's totally possible to use dmesg with either of them, and there is not much difference between the two of them. The short of it is that if you only want to work on the device, Android Terminal Emulator is the one for you. If you want advanced features or the ability to ssh to another machine, then you should use ConnectBot.

Android Terminal Emulator

Android Terminal Emulator is an easy to use Terminal Emulator available from F-Droid, as an APK, and from the Google Play store. It is intended to provide a terminal for your device, on your device.

ConnectBot Android Shell

ConnectBot Android Shell is a terminal emulator and secure shell client. It can be run in terminal emulator mode, or it can be used to connect via ssh to a remote machine. It can also be used to connect to a GNU/Linux chroot and launch some X applications if they are supported on your device.

Working in the Terminal Emulator

Once you've selected your terminal emulator, start it and enter the application on your device. The process for determining what hardware your device is using is roughly (turn off device)->(turn on device)->(run dmesg in emulator)-> (examine the results).

Step-by-Step

Usually, when you are doing this, you will be looking for your wifi hardware. Here is an example of how to discern what wifi hardware your device is using with dmesg.

Stop and Start the Hardware in Question

In order to make sure that a message from the device you are looking for is easy to find in the dmesg output, you need to make it do something that will be logged. The easiest way to do this, especially with wi-fi, to turn the device off, then back on, then immediately run dmesg and examine the output. Just use the interface on your Android device.

Run dmesg, Optionally Save the Output to a File

Immediately after you turn your wi-fi off and on, open the terminal emulator and type:

dmesg

to display the output immediately, or use:

dmesg > wifi_device_log.log

to save the output to a file on the device and:

cat wifi_device_log.log

to view the output.

If you want to save the output file to your work machine, you will need to use "adb shell" to connect to your device and pipe the output of the command to a file on your work device.

adb shell dmesg > wifi_device_log.log

Examine the Output to Find the Device

The output of dmesg can seem confusing at first, but what you need to find is fairly straightforward. Just look for every line in the output which has the phrase wlan0. From these lines, information can be gleaned about what wireless driver is in use, whether it requires a proprietary firmware, or and most of the time reveal the actual hardware. Right now, the only phone I have, however, is one of the really, absurdly cheap phones(L35g) and the only information that can be gathered from this particular phone is that the phone uses a proprietary driver.

<4>[   27.461203] wlan: module license 'Proprietary' taints kernel.

But, on an even slightly better phone (like the Samsung Galaxy Centura), a line like this will reveal the wireless card.

<6>[   34.082345] ADDRCONF(NETDEV_UP): wlan0'Card type will be here': link is not ready

Power Tools for Use with dmesg, the Advantages of Busybox

If you've never used grep before, prepare to meet your best friend. Grep stands for GNU regular expression parser but you don't care about that.

For example, here is the dmesg output of the LG Optimus Logic(l35g) filtered with grep.

cat wifi_device_log.log | grep wlan
    <3>[    2.625814] init: cannot find '/system/bin/wlan_tool', disabling 'wlan_tool'
    <4>[   27.461203] wlan: module license 'Proprietary' taints kernel.
    <6>[   34.082345] ADDRCONF(NETDEV_UP): wlan0: link is not ready
    <6>[   34.838541] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    <6>[   53.944377] ADDRCONF(NETDEV_UP): wlan0: link is not ready
    <6>[   55.327871] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    <7>[   65.913191] wlan0: no IPv6 routers present

Further Citations

• How do I find out what Wi-Fi Chipset my phone has Android Stack Exchange, GAThrawn, Gili