Re: [PATCH 2/3] ACPI / hotplug: Fix PCI host bridge hot removal

From: Rafael J. Wysocki
Date: Mon Nov 18 2013 - 16:26:54 EST


On Monday, November 18, 2013 11:10:05 AM Toshi Kani wrote:
> On Thu, 2013-11-14 at 00:16 +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Since the PCI host bridge scan handler does not set hotplug.enabled,
> > the check of it in acpi_bus_device_eject() effectively prevents the
> > root bridge hot removal from working after commit a3b1b1ef78cd
> > (ACPI / hotplug: Merge device hot-removal routines). However, that
> > check is not necessary, because the other acpi_bus_device_eject()
> > users, acpi_hotplug_notify_cb and acpi_eject_store(), do the same
> > check by themselves before executing that function.
> >
> > For this reason, remove the scan handler check from
> > acpi_bus_device_eject() to make PCI hot bridge hot removal work
> > again.
>
> I am curious why the PCI host bridge scan handler does not set
> hotplug.enabled. Is this how it disables hotplug via sysfs eject but
> enables via ACPI notification?

It just doesn't register for hotplug at all. I guess it could set that
bit alone, but then it would be quite confusing and the check is not
necessary anyway.

Thanks,
Rafael

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