4.15-stable review patch. If anyone has any objections, please let me know.
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From: Viresh Kumar viresh.kumar@linaro.org
[ Upstream commit 1d0d064307cbfd8546841f6e9d94d02c55e45e1e ]
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.
Before the above commit, the default transition delay was set to 200 ms for a transition_latency of 200000 ns. Lets revert back to that transition delay value to fix it. Note that several other transition delay values were tested like 20 ms and 30 ms and none of them have resolved system hang issue completely.
Fixes: e948bc8fbee0 (cpufreq: Cap the default transition delay value to 10 ms) Reported-by: Meelis Roos mroos@linux.ee Suggested-by: Rafael J. Wysocki rjw@rjwysocki.net Signed-off-by: Viresh Kumar viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cpufreq/longhaul.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/cpufreq/longhaul.c +++ b/drivers/cpufreq/longhaul.c @@ -894,7 +894,7 @@ static int longhaul_cpu_init(struct cpuf if ((longhaul_version != TYPE_LONGHAUL_V1) && (scale_voltage != 0)) longhaul_setup_voltagescaling();
- policy->cpuinfo.transition_latency = 200000; /* nsec */ + policy->transition_delay_us = 200000; /* usec */
return cpufreq_table_validate_and_show(policy, longhaul_table); }