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

[Shilimkar, Santosh]

On Wed, Aug 8, 2012 at 4:24 PM, Rajendra Nayak <rnayak at 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 at ti.com>
> Cc: <linux-pm at 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)
                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;