The per-device PM QoS locking requires a spinlock to be used. The reasons
are:
- an alignement with the PM QoS core code, which is used by the per-device
PM QoS code for the constraints lists management. The PM QoS core code
uses spinlocks to protect the constraints lists,
- some drivers need to use the per-device PM QoS functionality from
interrupt context or spinlock protected context.
An example of such a driver is the OMAP HSI (high-speed synchronous serial
interface) driver which needs to control the IP block idle state
depending on the FIFO empty state, from interrupt context.
Reported-by: Djamil Elaidi <d-elaidi@ti.com>
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
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