Re: [PATCH 1/6] PCI: acpiphp: do not check for SLOT_ENABLED in enable_device()
From: Bjorn Helgaas
Date: Tue Jul 02 2013 - 12:41:16 EST
On Mon, Jul 1, 2013 at 7:29 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
>
On Monday, July 01, 2013 09:36:13 PM Mika Westerberg wrote:
>
> On Mon, Jul 01, 2013 at 04:01:37PM +0200, Rafael J. Wysocki wrote:
>
> > > Given the fact that SLOT_ENABLED is only checked in acpiphp_enable_slot()
>
> > > (after this patch) and that /sys/bus/pci/slots/*/power uses SLOT_POWEREDON
>
> > > anyway, should we remove the whole flag?
>
> >
>
> > Sure, if it is not necessary any more, we should remove it.
>
>
>
> Well, there is one thing that changes due that. Once the flag is gone
>
> userspace can do 'echo 1 > /sys/bus/pci/slots/*/power' several times and
>
> the slot is always re-enumerated.
>
>
>
> If that is not acceptable we should probably move the SLOT_ENABLED check
>
> closer to acpiphp_core:enable_device() and drop it from here, so that we
>
> always re-enumerate on Bus Check event but userspace can only do enable
>
> once (we still re-enumerate on Bus Check).
>
>
Yes, that sounds like the right thing to do.
Is it actually a problem if we re-enumerate every time userspace does
'echo 1 > /sys/bus/pci/slots/*/power'? I assume re-enumeration is a
no-op if nothing has changed.
Bjorn
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