Nicholas Piggin <npig...@gmail.com> writes: > 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.
Hah yep, :face-with-cold-sweat: I created an issue so hopefully we don't forget: https://github.com/linuxppc/issues/issues/408 cheers