linux-kernel - Re: [patch 2.6.21-rc5-git] make /proc/acpi/wakeup more useful

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Message-Id: <1176086185.2650.28.camel@localhost.localdomain>
Date:	Mon, 09 Apr 2007 10:36:25 +0800
From:	Zhang Rui <rui.zhang@...el.com>
To:	David Brownell <david-b@...bell.net>, Greg KH <greg@...ah.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>, lenb@...nel.org,
	"linux-acpi@...r" <linux-acpi@...r.kernel.org>,
	Linux Kernel list <linux-kernel@...r.kernel.org>
Subject: Re: [patch 2.6.21-rc5-git] make /proc/acpi/wakeup more useful

On Sat, 2007-04-07 at 13:08 -0700, David Brownell wrote:
> On Friday 06 April 2007 10:01 pm, Greg KH wrote:
> 
> > Are you _sure_ you have a 1-to-1 relationship here?  No multiple devices
> > pointing to the same acpi node?  Or the other way around?  If so, you
> > are going to have to change the name to be something more unique.
> 
> I've wondered that too.  The short answer:  APCI only supports 1-1
> here.
Right.
>   It will emit warnings if it tries to bind more than one ACPI
> device to a given "real" device ... but errors the other way are
> silently ignored.
> 
My understanding is different.
First, one "real" device can only have one device.archdata.acpi_handle,
which means it can only be bound to one ACPI device.
Second, AE_ALREADY_EXISTS will be returned when ACPI tries to bind more
than one "real" devices to the same ACPI device.
> By adding a warning over this create-links patch, I found that the
> system in the $SUBJECT patch (and likely every ACPI system) has
> two different nodes that correspond to one ACPI node:
> 
> 	/sys/devices/pci0000:00 ... pci root node
> 	/sys/devices/pnp0/00:00 ... id PNP0a03
> 	/sys/devices/acpi_system:00/device:00/PNP0A03:00 ... ditto
> 
> Arguably that's too many sysfs nodes for one device...
> 
> Plus, there's the issue of flakey ACPI tables; in the $SUBJECT patch
> both MDM and AUD nodes exist in the ACPI namespace, but they could
> only refer to one PCI device (with MDM as the wakeup source, not AUD
> as listed in the table).  Or maybe that's another case where the ACPI
> code isn't handling the tables as sensibly as it might...
> 
Could you attach this acpidump please? :)

Thanks,
Rui
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