amd_pstate mode can be changed by writing the mode name to the `status`
sysfs. But some combinations are not working. Fix this issue by taking
care of the edge cases.
Before the fix the mode change combination test fails:
#./pst_test.sh
Test passed: from: disable, to
Test passed: from: disable, to disable
Test failed: 1, From mode: disable, to mode: passive
Test failed: 1, From mode: disable, to mode: active
Test failed: 1, From mode: passive, to mode: active
Test passed: from: passive, to disable
Test failed: 1, From mode: passive, to mode: passive
Test failed: 1, From mode: passive, to mode: active
Test failed: 1, From mode: active, to mode: active
Test passed: from: active, to disable
Test failed: 1, From mode: active, to mode: passive
Test failed: 1, From mode: active, to mode: active
After the fix test passes:
#./pst_test.sh
Test passed: from: disable, to
Test passed: from: disable, to disable
Test passed: from: disable, to passive
Test passed: from: disable, to active
Test passed: from: passive, to active
Test passed: from: passive, to disable
Test passed: from: passive, to passive
Test passed: from: passive, to active
Test passed: from: active, to active
Test passed: from: active, to disable
Test passed: from: active, to passive
Test passed: from: active, to active
Fixes: abd61c08ef ("cpufreq: amd-pstate: add driver working mode switch support")
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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