(In reply to Klaus Mueller from comment #530) > Hmm, if rev. 1 doesn't support MWAIT - why can it be a problem anyway > at the same time which must be fixed by disabling the usage of MWAIT? > I seem to miss something?
That's a good question but, frankly, I don't have a very exact answer to it right now. In order to understand what's *really* going on in the cstate detection code one would need to instrument at least acpi_processor_get_power_info_cst() and acpi_processor_ffh_cstate_probe() to figure out what exactly does the kernel parse from those CST objects and what it uses to try to enter idle. And do all that instrumentation on an affected system. My current suspicion is is that it tries to enter idle with misconfigured states and under certain conditions, it misses the wakeup, leading to the stall. This is all a conjecture anyway. Now my patch simply falls back to the good old idle entry on AMD where we simply do HLT and we won't even attempt to enter idle the ACPI way. Makes sense? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1690085 Title: Ryzen 1800X freeze - rcu_sched detected stalls on CPUs/tasks To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1690085/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
