From 16f1ed6df7731514273d5e62a75667ed9ab259c5 Mon Sep 17 00:00:00 2001 From: Jonas Aaberg Date: Tue, 6 Mar 2012 07:46:12 +0100 Subject: ARM: smp_twd: Only wait for reprogramming on active cpus During booting of cpu1, there is a short window where cpu1 is online, but not active where cpu1 is occupied by waiting to become active. If cpu0 then decides to schedule something on cpu1 and wait for it to complete, before cpu0 has set cpu1 active, we have a deadlock. This is just a work around to hide the original problem. ST-Ericsson Linux next: - ST-Ericsson ID: 419957 ST-Ericsson FOSS-OUT ID: Trivial Change-Id: I133e511cece4024375cc92a82f79bd799514d71d Signed-off-by: Jonas Aaberg Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/51514 Reviewed-by: QABUILD Reviewed-by: Rickard ANDERSSON --- arch/arm/kernel/smp_twd.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index c731ac2f0bd..007f7f6aee8 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -118,10 +118,14 @@ static int twd_cpufreq_transition(struct notifier_block *nb, * The twd clock events must be reprogrammed to account for the new * frequency. The timer is local to a cpu, so cross-call to the * changing cpu. + * + * Only wait for it to finish, if the cpu is active to avoid + * deadlock when cpu1 is spinning on while(!cpu_active(cpu1)) during + * booting of that cpu. */ if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE) smp_call_function_single(freqs->cpu, twd_update_frequency, - NULL, 1); + NULL, cpu_active(freqs->cpu)); return NOTIFY_OK; } -- cgit v1.2.3