On Tue, Dec 5, 2017 at 9:54 AM, Meelis Roos mroos@ut.ee wrote:
The commit e948bc8fbee0 ("cpufreq: Cap the default transition delay value to 10 ms") caused a regression on EPIA-M min-ITX computer where shutdown or reboot hangs occasionally with a print message like:
longhaul: Warning: Timeout while waiting for idle PCI bus cpufreq: __target_index: Failed to change cpu frequency: -16
This probably happens because the cpufreq governor tries to change the frequency of the CPU faster than allowed by the hardware.
With the above commit, the default transition delay comes to 10 ms for a transition_latency of 200 us. Set the default transition delay to 20 ms directly to fix this regression.
Fixes: e948bc8fbee0 ("cpufreq: Cap the default transition delay value to 10 ms") Cc: 4.14+ stable@vger.kernel.org # 4.14+ Reported-by: Meelis Roos mroos@linux.ee Suggested-by: Rafael J. Wysocki rjw@rjwysocki.net Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
drivers/cpufreq/longhaul.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c index c46a12df40dd..56eafcb07859 100644 --- a/drivers/cpufreq/longhaul.c +++ b/drivers/cpufreq/longhaul.c @@ -894,7 +894,7 @@ static int longhaul_cpu_init(struct cpufreq_policy *policy) if ((longhaul_version != TYPE_LONGHAUL_V1) && (scale_voltage != 0)) longhaul_setup_voltagescaling();
- policy->cpuinfo.transition_latency = 200000; /* nsec */
policy->transition_delay_us = 20000; /* usec */
return cpufreq_table_validate_and_show(policy, longhaul_table);
}
This patch also works on my EPIA-M board - tested 10+ times.
An on the last try just after sending the mail, it hung again in the same way as before - so maybe 20 is on the edge of being good.
OK, so can you please try to modify the patch to set transition_delay_us to 30000, say, and see if that's reliable?
Thanks, Rafael