Re: [Pcihpd-discuss] what is writing to /sys/bus/pci/slot/<slot_no>/power really supposed to do?

Gary Hade
2007-10-01T17:43:55Z

On Mon, Oct 01, 2007 at 10:08:58AM -0700, Kristen Carlson Accardi wrote:
> 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, This sounds a lot like the problem I was trying to address
with the "fix slot poweroff problem on systems without _PS3" patch
that I posted in June.
http://sourceforge.net/mailarchive/forum.php?thread_name=20070604232736.GA3239%40us.ibm.com&forum_name=pcihpd-discuss
It seems to be working fine on our systems.

Gary

--
Gary Hade
System x Enablement
IBM Linux Technology Center
503-578-4503 IBM T/L: 775-4503
garyhade@us.ibm.com