PREEMPT_RT, also known as "the rt patch" is a patchset ontop of the vanilla Linux kernel which helps provide bound timing guarantees for user task execution, a required property for any real-time application.
The rt patch has a long history out of mainline. What used to be a slow trickle of patches moving from the rt patch to mainline has now accelerated with the formation of the Real Time Linux LF project, which is actively funding the engineering work necessary to bring merge the patch into mainline.
However, long after the core PREEMPT_RT changes land in mainline, we'll still be stuck dealing with a long tail of problems in Linux's thousands of device drivers. The intent of this presentation is to describe the classes of problems in drivers which have detrimental impact to RT, why they cause issues on RT, and how they might be resolved."