Lessons Learned When Updating Userspace ABIs

Explore the challenges and solutions involved in updating userspace Application Binary Interfaces (ABIs) for I2C and SMBus technologies in Linux. Delve into the process of implementing the SMBus 3.x specification's increase in maximum block length from 32 to 255 bytes while maintaining compatibility with existing userspace applications. Learn about the careful planning, obstacles encountered, and decisions made to successfully provide this improvement to Linux users. Gain insights into the intricacies of evolving long-standing technologies and the importance of backward compatibility in system programming.