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author | Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> | 2014-04-28 18:54:42 (GMT) |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-04-28 23:22:53 (GMT) |
commit | 3221e55b72359c44ed75afbcf707710af5bc2d59 (patch) | |
tree | 85c6770b0fa26e90f10cc8e8c51d5cb2c8504bb7 /drivers/cpufreq/powernow-k6.c | |
parent | 237ede16ba5bcd4d6c612ea280518c48ca31986c (diff) | |
download | linux-3221e55b72359c44ed75afbcf707710af5bc2d59.tar.xz |
cpufreq: powernow-k6: Fix double invocation of cpufreq_freq_transition_begin/end
During frequency transitions, the cpufreq core takes the responsibility of
invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end()
for those cpufreq drivers that define the ->target_index callback but don't
set the ASYNC_NOTIFICATION flag.
The powernow-k6 cpufreq driver falls under this category, but this driver was
invoking the _begin() and _end() APIs itself around frequency transitions,
which led to double invocation of the _begin() API. The _begin API makes
contending callers wait until the previous invocation is complete. Hence,
the powernow-k6 driver ended up waiting on itself, leading to system hangs
during boot.
Fix this by removing the calls to the _begin() and _end() APIs from the
powernow-k6 driver, since they rightly belong to the cpufreq core.
(Note that during ->exit(), the powernow-k6 driver sets the frequency
without any help from the cpufreq core. So add explicit calls to the
_begin() and _end() APIs around that frequency transition alone, to take
care of that special case. Also, add a missing 'break' statement there.)
Fixes: 12478cf0c55e (cpufreq: Make sure frequency transitions are serialized)
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/powernow-k6.c')
-rw-r--r-- | drivers/cpufreq/powernow-k6.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c index 695a68c..78904e6 100644 --- a/drivers/cpufreq/powernow-k6.c +++ b/drivers/cpufreq/powernow-k6.c @@ -138,22 +138,14 @@ static void powernow_k6_set_cpu_multiplier(unsigned int best_i) static int powernow_k6_target(struct cpufreq_policy *policy, unsigned int best_i) { - struct cpufreq_freqs freqs; if (clock_ratio[best_i].driver_data > max_multiplier) { printk(KERN_ERR PFX "invalid target frequency\n"); return -EINVAL; } - freqs.old = busfreq * powernow_k6_get_cpu_multiplier(); - freqs.new = busfreq * clock_ratio[best_i].driver_data; - - cpufreq_freq_transition_begin(policy, &freqs); - powernow_k6_set_cpu_multiplier(best_i); - cpufreq_freq_transition_end(policy, &freqs, 0); - return 0; } @@ -229,8 +221,18 @@ static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) unsigned int i; for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { - if (clock_ratio[i].driver_data == max_multiplier) + if (clock_ratio[i].driver_data == max_multiplier) { + struct cpufreq_freqs freqs; + + freqs.old = policy->cur; + freqs.new = clock_ratio[i].frequency; + freqs.flags = 0; + + cpufreq_freq_transition_begin(policy, &freqs); powernow_k6_target(policy, i); + cpufreq_freq_transition_end(policy, &freqs, 0); + break; + } } return 0; } |