> 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@xxxxxxxxxxxxxxx> # 4.14+
> Reported-by: Meelis Roos <mroos@xxxxxxxx>
> Suggested-by: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
> 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.
Sorry it took so long to test, it was a remote computer.
--
Meelis Roos (mroos@xxxxxxxx)