On 2025-06-18 07:34:25 [-0400], Michael Schanne wrote: > I found my issue, I am using several SCHED_FIFO threads, one was spinning > waiting on a timer to update, another thread which was supposed to update > the timer count is higher priority, but with the RT patch applied there is > also a ktimers thread set to RT priority 1, so it was never getting a > chance to run and my timer would never fire. I adjusted the ktimers thread > to a higher priority and things started working again. This thread does > not exist in the vanilla kernel even with CONFIG_PREEMPT_RT enabled, so > that is why I wasn't seeing it there. The i915 driver was a red herring. Okay not the i915. The ktimers thread wakes only SCHED_OTHER tasks. The SCHED_FIFO/RR threads should be woken up directly (without the need of the ktimers thread). So you are not using clock_nanosleep() but something like a POSIX timer? > Thanks, > Mike Sebastian
