>
>--------- Original Message ---------
>Sender : Rafael J. Wysocki <r...@rjwysocki.net>
>Date : 2017-06-01 08:58 (GMT+9)
>Title : Re: FW: [4.12 regression] "cpufreq: intel_pstate: Active mode P-state
>limits rework"
>
>On Monday, May 29, 2017 02:18:52 AM Jongman Heo wrote:
>>
>> Hi,
>>
>> FYI, 4.12-rc3 still has this issue.
>>
>>
>> --------- Original Message ---------
>> Sender : 허종만 <jongman....@samsung.com>
>> Date : 2017-05-16 13:25 (GMT+9)
>> Title : [4.12 regression] "cpufreq: intel_pstate: Active mode P-state
>> limits rework"
>>
>>
>> Hi,
>>
>> With 4.12-rc1 (Linus git), booting fails due to kernel panic, at
>> intel_pstate_register_driver+0x56/0x110.
>> I can't copy the whole trace from the graphic console, it looks like below.
>>
>> Call Trace:
>> intel_pstate_init
>> intel_pstate_setup
>> do_one_initcall
>> set_debug_rodata
>> kernel_init_freeable
>> rest_init
>> kernel_init
>> ret_from_fork
>> Code: ...
>> RIP: intel_pstate_register_driver+0x56/0x110 RSP: ffffa3a98000bd80
>> ...
>
>I guess this is a division by 0 due to the unmet assumption that the
>denominator
>in min_perf_pct_min() will always be nonzero.
>
>If this guess is correct, the patch below should help, so can you please test
>it?
>
>Thanks,
>Rafael
>
>
>---
> drivers/cpufreq/intel_pstate.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
>Index: linux-pm/drivers/cpufreq/intel_pstate.c
>===================================================================
>--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
>+++ linux-pm/drivers/cpufreq/intel_pstate.c
>@@ -571,9 +571,10 @@ static inline void update_turbo_state(vo
> static int min_perf_pct_min(void)
> {
> struct cpudata *cpu = all_cpu_data[0];
>+ int turbo_pstate = cpu->pstate.turbo_pstate;
>
>- return DIV_ROUND_UP(cpu->pstate.min_pstate * 100,
>- cpu->pstate.turbo_pstate);
>+ return turbo_pstate ?
>+ DIV_ROUND_UP(cpu->pstate.min_pstate * 100, turbo_pstate) : 0;
> }
>
> static s16 intel_pstate_get_epb(struct cpudata *cpu_data)
>
>
>
Hi,
Your patch fixes the issue.
Thanks~.
Jongman.
