On Monday 23 December 2013 12:25 PM, Bjørn Mork wrote:
> That's correct.  The immediate result of the failure is exactly the
> same.

Okay..

> The difference is that a subsequent resume would restore the cpufreq
> device whether it existed or not.  That made a complete suspend/resume
> fix up any missing cpufreq device, e.g. one that was removed by a
> previous error.

I see.. Please see if below patch fixes it for you, it should :)


From: Viresh Kumar <viresh.ku...@linaro.org>
Date: Mon, 23 Dec 2013 13:19:47 +0530
Subject: [PATCH] cpufreq: try to resume policies which failed on last resume
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

__cpufreq_add_dev() can fail sometimes while we are resuming our system.
Currently we are clearing all sysfs nodes for cpufreq's failed policy as that
could make userspace unstable. But if we suspend/resume again, we should atleast
try to bring back those policies.

This patch fixes this issue by clearing fallback data on failure and trying to
allocate a new struct cpufreq_policy on second resume.

Reported-by: Bjørn Mork <bj...@mork.no>
Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
 drivers/cpufreq/cpufreq.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index fab042e..7523d35 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1010,16 +1010,24 @@ static int __cpufreq_add_dev(struct device *dev, struct 
subsys_interface *sif,
        read_unlock_irqrestore(&cpufreq_driver_lock, flags);
 #endif

-       if (frozen)
+       if (frozen) {
                /* Restore the saved policy when doing light-weight init */
                policy = cpufreq_policy_restore(cpu);
-       else
+
+               /*
+                * As we failed to resume cpufreq core last time, lets try to
+                * create a new policy.
+                */
+               if (!policy)
+                       frozen = false;
+       }
+
+       if (!frozen)
                policy = cpufreq_policy_alloc();

        if (!policy)
                goto nomem_out;

-
        /*
         * In the resume path, since we restore a saved policy, the assignment
         * to policy->cpu is like an update of the existing policy, rather than
@@ -1112,8 +1120,14 @@ err_get_freq:
        if (cpufreq_driver->exit)
                cpufreq_driver->exit(policy);
 err_set_policy_cpu:
-       if (frozen)
+       if (frozen) {
+               /*
+                * Clear fallback data as we should try to make things work on
+                * next suspend/resume
+                */
+               per_cpu(cpufreq_cpu_data_fallback, cpu) = NULL;
                cpufreq_policy_put_kobj(policy);
+       }
        cpufreq_policy_free(policy);

 nomem_out:

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