From patchwork Mon Dec 26 11:46:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: parisc: Mark cr16 clocksource unstable on SMP systems From: Helge Deller X-Patchwork-Id: 9488601 Message-Id: <20161226114601.GA5893@p100.box> To: linux-parisc@vger.kernel.org, James Bottomley , John David Anglin Date: Mon, 26 Dec 2016 12:46:01 +0100 The cr16 interval timer of each CPU is not syncronized to other cr16 timers in other CPUs in a SMP system. So, delay the registration of the cr16 clocksource until all CPUs have been detected and then mark it as unstable and lower it's rating before registering it at the clockource framework. This patch fixes the stalled CPU warnings which we have seen since introduction of the cr16 clocksource. Signed-off-by: Helge Deller --- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c index 325f30d..47ef8fd 100644 --- a/arch/parisc/kernel/time.c +++ b/arch/parisc/kernel/time.c @@ -289,9 +289,26 @@ void __init time_init(void) cr16_hz = 100 * PAGE0->mem_10msec; /* Hz */ - /* register at clocksource framework */ - clocksource_register_hz(&clocksource_cr16, cr16_hz); - /* register as sched_clock source */ sched_clock_register(read_cr16_sched_clock, BITS_PER_LONG, cr16_hz); } + +static int __init init_cr16_clocksource(void) +{ + /* + * The cr16 interval timers are not syncronized across CPUs, so mark + * them unstable and lower rating on SMP systems. + */ + if (num_online_cpus() > 1) { + clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE; + clocksource_cr16.rating = 0; + } + + /* register at clocksource framework */ + clocksource_register_hz(&clocksource_cr16, + 100 * PAGE0->mem_10msec); + + return 0; +} + +device_initcall(init_cr16_clocksource);