linux-kernel - Re: [PATCH] ACPI: Add sysfs interface for acpi device wakeup

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Date:	Wed, 19 Mar 2008 22:37:24 +0800
From:	Yi Yang <yi.y.yang@...el.com>
To:	trenn@...e.de
Cc:	Zhang Rui <rui.zhang@...el.com>,
	Maxim Levitsky <maximlevitsky@...il.com>, david-b@...bell.net,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	lenb@...nel.org, acpi-bugzilla@...ts.sourceforge.net,
	Holger Macht <hmacht@...e.de>
Subject: Re: [PATCH] ACPI: Add sysfs interface for acpi device wakeup

> Any news on this?
> I ran into a problem with the current implementation:
> 
> If one GPE is tight to several devices you get a message:
> echo XYZ >/tmp/acpi/wakeup
> ACPI: 'XXX' and 'XYZ' have the same GPE, can't disable/enable one
> seperately
> ACPI: 'YYY' and 'XYZ' have the same GPE, can't disable/enable one
> seperately
> and none of the devices are activated to be able to wake the machine up.
> Which I expect is wrong, all should be enabled/disabled then IMO, but
> it's probably not worth much fixing in /proc/acpi/...
"Can't disable/enable one seperately" is just a warning, all the devices
with the same GPE can be disabled/enabled once.

> 
> The correct interface to use seem to be:
> drivers/base/power/sysfs.c
wakeup flag in this driver is a generic software flag in "struct
device", but the wakeup flag you see in /proc/acpi/wakeup is a hardware
wakeup flag in ACPI device, all the wakeup events triggered by hardware
devices are handled by ACPI driver.

But i indeed regret wakeup flags in /sys/... and /proc/acpi/wakeup
haven't any association. They should be consolidated in my opinion.

Zhang Rui said they are doing it, but i didn't get any information about
progress, i completely agree it should be done ASAP.

If you need to enbale wakeup, you.d better enable wakeup flag in
both /proc/acpi/wakeup and /sys/..., i can use USB mouse to wake up my
machine from S3.

> But this is rather broken?
> Here an output of /proc/acpi/wakeup and /sys/...:
> for x in `find /sys/ |grep wakeup`;do if [ $(cat $x) ];then echo $x; cat $x;fi;done
> /sys/devices/pnp0/00:04/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.7/usb4/4-5/power/wakeu
> enabled
> /sys/devices/pci0000:00/0000:00:1d.7/usb4/4-1/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.7/usb4/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.7/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.2/usb3/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.1/usb2/power/wakeup
> enabled
> /sys/devices/pci0000:00/0000:00:1d.0/usb1/power/wakeup
> enabled
> trenn@...avinsky:/extern/trenn/packages/home:trenn> cat /proc/acpi/wakeup 
> Device  S-state   Status   Sysfs node
> PCI0      S5     disabled  no-bus:pci0000:00
> 
> I still think (from comments in drivers/base/power/sysfs.c, not sure
> whether it really is that appropriate) it is wakeup sysfs file that
> should be used for this.
> I wonder why each device has a wakeup file, it should be enough to
> create them dynamically if wakeup enable/disable is supported for a
> specific device?
> Also a second file is missing from which state (S3,S4,S5) the device can
> wake the machine up.
> 
> If there can be multiple devices for one GPE, this information (the
> power directory of multiple devices) could be linked together in sysfs?
> E.g.
> /sys/devices/pci0000:00/0000:00:1d.7/usb4/power/wakeup
> is a link to:
> /sys/devices/pci0000:00/0000:00:1d.2/usb3/power/wakeup
> If both are using one wake-up GPE.
> 
> Also if the ACPI device caught through acpi_get_physical device is a PCI
> bridge, it should get evaluated what is behind the bridge and this
> device (e.g. a network card) should get the wakeup stuff set up, not the
> bridge?
> 
> Does someone still look at this?
> If not, shall I or is it on some queue?
> Should this be discussed a bit more detailed first?
> 
>    Thomas
> 
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