adb shell command to Turn ON Bluetooth & make it discoverable

bluetooth

We can turn on the Bluetooth using adb command as below, once you type this on your desktop/laptop, Android will prompt the user on Mobile / Android device for allowing permissions to turn ON the bluetooth, like below We can make the Bluetooth Discoverable using adb command as below, Subscribe with Valid Email Id to … Read more

Writing first Linux kernel Module

We will try to understand the simple kernel driver which initially we will compile for Ubuntu host and later for a embedded hardware. Create a Makefile, [Note: Make sure you have added TAB before “make” in above makefile ] Now, compile this kernel module for Ubuntu based host, The “tree” command shows the output files … Read more

How to Enable and Disable Wireless / WiFi from command line ?

Rfkill is a tool for enabling and disabling wireless devices. We use “rfkill list” command as below to check the list of available wireless devices on our machine. This command returns the devices and its index 0, 1, 2 as below, As seen above we have a WiFi, LAN and Bluetooth supported and ON in … Read more

How to Turn ON and Turn OFF Bluetooth from command line ?

Rfkill is a tool for enabling and disabling wireless devices. Using “rfkill list” command we first check the list of available wireless devices supported in our hardware as, As seen above we have a WiFi, LAN and Bluetooth supported and ON in my laptop. Now lets try turning ON & OFF this Bluetooth device using … Read more

How to extract files from jffs2 root filesystem image ?

[ Note: following commands has been tried on ubuntu 16.04, but should work on other Linux distros as well ] Lets create a temporary device node in /tmp as, brw-r–r– 1 root root 31, 0 Aug 23 00:21 /tmp/mtdblock0 Now lets use dd command to write jffs2 binary rootfs to temporary device node we created … Read more

Creating jffs2 filesystem image for embedded target platform

What is JFFS2 ?=> JFFS2 is a log-structured file system designed for use on flash devices in embedded systems. Rather than using a kind of translation layer on flash devices to emulate a normal hard drive, as is the case with older flash solutions, it places the filesystem directly on the flash chips.JFFS2 was developed … Read more

insmod: ERROR: could not insert module hello.ko

We tried to write a simple class driver framework which will create a directory in /sys/class, we were able to compile the code but got the following error while trying to install the driver as, Solution : The function __class_create is exported only for GPL modules (exported with EXPORT_SYMBOL_GPL). So, you need to use a … Read more

Understanding sysfs and USB

As we know the USB itself is a very complex peripheral to understand and work upon for development, due to such complexity the sysfs representation of USB bus and the peripherals attached to it is also complex. We can now see how many root hubs our machine has as below, This shows that it has … Read more

How to measure Network Throughput using iperf ?

iPerf3 is a tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to timing, buffers and protocols (TCP, UDP, SCTP with IPv4 and IPv6). For each test it reports the bandwidth, loss, and other parameters.  In this post, we will demo the steps required for … Read more