Excerpts from Nicholas Piggin's message of April 21, 2022 12:07 pm: > 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...
tglx merged it into his tree, so we could try again after its upstream. https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=timers/core&id=62c1256d544747b38e77ca9b5bfe3a26f9592576 I'm kind of worried the patch will explode some strange clock event device in an obscure way so we may wait for a release or two first. Thanks, Nick