what is writing to /sys/bus/pci/slot/<slot_no>/power really supposed to do?

Kristen Carlson Accardi
2007-10-01T17:14:12Z

Hi,
I notice in acpiphp that the code path for powering down the slot
via sysfs does not execute the _EJ0 method, but instead simply
looks for _PS3 and of couse disables all the bridges and devices.
I suppose this could be valid depending on your definition of what
/sys/bus/pci/slots/<slot_no>/power should do.

Is it intended to just power down the adapter that's in the slot,
or is it intended to make the adapter in the slot able to be removed?
If it's intended to make the adapter able to be removed, shouldn't
we be calling _EJ0?

As a comparison, in pciehp when the sysfs power file is written,
we do actually go out and send the commands to the hotplug controller
to physically power off the slot.

Kristen