PM / domains: Rework governor code to be more consistent
The genpd governor currently uses negative PM QoS values to indicate the "no suspend" condition and 0 as "no restriction", but it doesn't use them consistently. Moreover, it tries to refresh QoS values for already suspended devices in a quite questionable way. For the above reasons, rework it to be a bit more consistent. First off, note that dev_pm_qos_read_value() in dev_update_qos_constraint() and __default_power_down_ok() is evaluated for devices in suspend. Moreover, that only happens if the effective_constraint_ns value for them is negative (meaning "no suspend"). It is not evaluated in any other cases, so effectively the QoS values are only updated for devices in suspend that should not have been suspended in the first place. In all of the other cases, the QoS values taken into account are the effective ones from the time before the device has been suspended, so generally devices need to be resumed and suspended again for new QoS values to take effect anyway. Thus evaluating dev_update_qos_constraint() in those two places doesn't make sense at all, so drop it. Second, initialize effective_constraint_ns to 0 ("no constraint") rather than to (-1) ("no suspend"), which makes more sense in general and in case effective_constraint_ns is never updated (the device is in suspend all the time or it is never suspended) it doesn't affect the device's parent and so on. Finally, rework default_suspend_ok() to explicitly handle the "no restriction" and "no suspend" special cases. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Tero Kristo <t-kristo@ti.com> Reviewed-by: Ramesh Thomas <ramesh.thomas@intel.com>
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