The Seven Year Leap - Updating a Product from Linux 2.6 to 4.15 - A Real-World Project Case Study

Explore a real-world case study of updating a Linux-based product from kernel 2.6 to 4.15 in this conference talk. Delve into the challenges, decision-making process, and technical aspects of upgrading an OMAP3-based Android device's kernel. Learn about the issues that prompted the upgrade, effort estimation, and management approval. Discover which components worked seamlessly and which required extensive modifications, including insights on GPU driver complications and running Android KitKat on a newer kernel. Gain valuable knowledge on navigating major kernel version jumps, including tips on driver updates, device tree modifications, and maintaining compatibility with older Android versions. Benefit from the speaker's extensive experience in embedded software development and understand the practical implications of such a significant kernel upgrade in niche market devices.

Intro
Not the first talk related to working with older kernels
Where are you on the kernel development spectrum?
What was the device in this project?
Older kernel problems NOT resolved
Making the case for the upgrade
Finding the starting point
Getting to a bash prompt
Newer kernel, newer boot loader
Check the new kernel has fixed the blocking issues
Re-adding support for peripherals to new kernel
Example of almost doing it wrong: Backlight
Touchscreen
Display: A bigger challenge
Re-enabled a driver... in the wrong subsystem?
RFBI being stubborn
Regulators
Putting Android back on again
Staying with Kitkat on 4.x kernel
First usable release
Initial feedback from test team
Re-adding PowerVR SGX rendering support
A whole bunch of other bits
How long did it take, in retrospect?
Points to remember when jumping major kernel versions