1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking Benchmarking Platform
Phoromatic Test Orchestration

Reverse-Engineering USB Keyboards For Linux Support

Hardware

Published on 12 July 2012 06:17 AM EDT
Written by Michael Larabel in Hardware
16 Comments

For those interested in reverse-engineering USB keyboards (or other input devices), there's a short yet effective guide by Julien Danjou for reverse-engineering a Logitech keyboard in order to provide Linux support.

Julien was using a Logitech K750 keyboard, which is USB-based and wireless, but what makes it different is that the keyboard is solar-powered rather than relying upon disposable batteries. While the Logitech keyboard works under Linux, there's no support for monitoring the battery charge level outside of Windows. This led to writing open-source code in order to read the battery status and light meter from Linux. The actual keyboard works under Linux due to the "Unifying" receiver and more recently the added "hid-logitech-dj" Linux kernel driver.

In his Logitech K750 keyboard and Unifying Receiver Linux support blog post, Julien Danjou goes over the process of writing the support. He used VirtualBox virtualization of Windows since this means of Oracle virtualization supports USB pass-through with hot-plugging support. KVM/QEMU also supports USB pass-through, but Oracle's VM VirtualBox implementation works better for USB. With Windows running within a VirtualBox instance, he used the "usbmon" kernel driver paired with Wireshark to understand the Logitech USB HID protocol by reverse-engineering with snooping the USB packets.

With Windows virtualized and talking to the Logitech keyboard using its respective driver while sniffing out the USB packets from Linux, Julien was able to understand what was happening for the light meter and battery status. From there, he wrote a small libusb-powered application to obtain this information cleanly under Linux. In the end it worked, but there's still room for improvement. See Julien's blog post for details in full.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux News
  1. KDE Marks Four Years In Its Process Of Porting To Wayland
  2. Btrfs In Linux 4.2 Brings Quota Updates, Many Fixes
  3. Latest Rumor Pegs Microsoft Wanting To Buy AMD
  4. The Next-Gen Phoronix Site Experience Is Almost Ready
  5. Exciting Features Merged So Far For The Linux 4.2 Kernel
  6. Mesa 10.6.1 Brings A Bug-Fix For Dota 2 Reborn
  7. DragonFlyBSD 4.2 Released: Brings Improved Graphics & New Compiler
  8. Wine-Staging 1.7.46 Improves The OS X Experience
  9. The State & Complications Of Porting The Unity Editor To Linux
  10. Libreboot Now Supports An AMD/ASUS Motherboard
Latest Articles & Reviews
  1. How KDE VDG Is Trying To Make Open-Source Software Beautiful
  2. Attempting To Try Out BCache On The Linux 4.1 Kernel
  3. CompuLab's Fitlet Is A Very Tiny, Fanless, Linux PC With AMD A10 Micro
  4. AMD A10-7870K Godavari: RadeonSI Gallium3D vs. Catalyst Linux Drivers
Most Viewed News This Week
  1. Kubuntu 15.10 Could Be The End Of The Road
  2. Linus Is Looking Forward To Merging KDBUS, But Not Convinced By Performance
  3. NVIDIA Starts Supplying Open-Source Hardware Reference Headers
  4. KDBUS Won't Be Pushed Until The Linux 4.3 Kernel
  5. Linux 4.2 Kernel Gets Port To New Processor Architecture
  6. The Staging Pull For Linux 4.2: "Big, Really Big"
  7. EXT4 Has Many Cleanups & Fixes For Linux 4.2
  8. SteamOS "Brewmaster" Is Valve's New Debian 8.1 Based Version