Excerpts from Michal Suchánek's message of April 21, 2022 12:28 am: > Hello, > > On Thu, Apr 21, 2022 at 12:16:57AM +1000, Michael Ellerman wrote: >> This is a partial revert of commit 0faf20a1ad16 ("powerpc/64s/interrupt: >> Don't enable MSR[EE] in irq handlers unless perf is in use"). >> >> Prior to that commit, we always set the decrementer in >> timer_interrupt(), to clear the timer interrupt. Otherwise we could end >> up continuously taking timer interrupts. >> >> When high res timers are enabled there is no problem seen with leaving >> the decrementer untouched in timer_interrupt(), because it will be >> programmed via hrtimer_interrupt() -> tick_program_event() -> >> clockevents_program_event() -> decrementer_set_next_event(). >> >> However with CONFIG_HIGH_RES_TIMERS=n or booting with highres=off, we > > How difficult is it to detect this condition? > > Maybe detecting this could be just added?
Possibly not too difficult but I'd like to see if we can get this to work in core timer code - https://lists.ozlabs.org/pipermail/linuxppc-dev/2022-April/242212.html I'll resend as a patch and see what flamage I get... Thanks, Nick