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Srivatsa S. Bhat authored
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 longhaul 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 longhaul 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 longhaul driver, since they rightly belong to the cpufreq core. (Note that during module_exit(), the longhaul 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.) Fixes: 12478cf0 (cpufreq: Make sure frequency transitions are serialized) Reported-and-tested-by:
Meelis Roos <mroos@linux.ee> Signed-off-by:
Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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