Re: [PATCH 1/2] cpufreq: OMAP: Handle missing frequency table on SMP systems

[Kevin Hilman <khilman@ti.com>]

"Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:

> On Wed, Aug 8, 2012 at 4:24 PM, Rajendra Nayak <rnayak@ti.com> wrote:
>>
>> On OMAP4, if the first CPU fails to get a valid frequency table (this
>> could happen if the platform does not register any OPP table), the
>> subsequent CPU instances end up dealing with a NULL freq_table and
>> crash. Add a check for a NULL freq_table to help error the rest
>> of the CPU instances out.
>>
>> Signed-off-by: Rajendra Nayak <rnayak@ti.com>
>> Cc: <linux-pm@vger.kernel.org>
>> ---
>>  drivers/cpufreq/omap-cpufreq.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/omap-cpufreq.c
>> b/drivers/cpufreq/omap-cpufreq.c
>> index 17fa04d..0ee824c 100644
>> --- a/drivers/cpufreq/omap-cpufreq.c
>> +++ b/drivers/cpufreq/omap-cpufreq.c
>> @@ -221,7 +221,7 @@ static int __cpuinit omap_cpu_init(struct
>> cpufreq_policy *policy)
>>         if (atomic_inc_return(&freq_table_users) == 1)
>>                 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
>>
>> -       if (result) {
>> +       if (result || !freq_table) {
>>                 dev_err(mpu_dev, "%s: cpu%d: failed creating freq
>> table[%d]\n",
>>                                 __func__, policy->cpu, result);
>>                 goto fail_ck;
>
> The freq_table use count seems to be buggy in that case.
> Something like below should fix the issue.
> Feel free to update your patch with below if you agree.
>
> diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
> index 17fa04d..fd97c3d 100644
> --- a/drivers/cpufreq/omap-cpufreq.c
> +++ b/drivers/cpufreq/omap-cpufreq.c
> @@ -218,7 +218,7 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *po
>
>         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
>
> -       if (atomic_inc_return(&freq_table_users) == 1)
> +       if (freq_table)

I think you meant 'if (!freq_table)' ?

Kevin

>                 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
>
>         if (result) {
> @@ -227,6 +227,7 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *po
>                 goto fail_ck;
>         }
>
> +       atomic_inc_return(&freq_table_users);
>         result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
>         if (result)
>                 goto fail_table;
> --
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