I am looking through the IO device Runtime PM implementation on Linux (Fedora 16).  There are some questions that
need you help to clarify for me,  here they are


1)       For those IO devices that could not be waked up through ACPI GPEs or native PCI Express PME ,  can  Runtime suspend/resume be used ?



2)       In  rtl8169's implementation of  Runtime suspend/resume, there is a  routine rtl8169_check_link_status(), which  always invokes
       pm_schedule_suspend() if the Link line is dis-connected,  pm_request_resume() if the Link line is connected.  And rtl8169_check_link_status
      itself is called through the transmit time out handler, which invokes rtl8169_reset_task.     So rtl8169_check_link_status,  as an opportunity point
       for Runtime PM for its network interface ,  does not require any  wake-up signaling, right?   The only Hardware Level requirement for rtl1869_check_link_status
       to work in this way is  that  the  link status register can always be read  no matter the network interface is in  off or on status.


3)      How should the Block IO adapter devices like the SCSI Controller or FC Adapters  should do  Runtime PM ?   In my understand,  these
      Devices should be auto-suspended when there is no IO request pending for a predefined duration,  and they should be resumed when
     a new IO request issued by the block layer.  So these devices may use a different wake up method that has no dependency on  PCI Express PME or
     ACPI GPE.






n  Qianfeng Zhang