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

[Maxim Levitsky]

On Thursday, 10 January 2008 00:21:46 Yi Yang wrote:
> Subject: ACPI: convert procfs to sysfs for /proc/acpi/wakeup
> From: Yi Yang <yi.y.yang@xxxxxxxxx>
> 
> /proc/acpi/wakeup is deprecated but it has to exist because
> we haven't a sysfs interface to replace it yet, this patch
> converts /proc/acpi/wakeup to sysfs interface, under every
> acpi device sysfs node, a user can see a directory "wakeup"
> if the acpi device can support wakeup, there are six files
> under this directory:
> 
> acpi_bus_id  bus_id  pci_id  run_wakeup  sleep_state  status
> 
> All the files are read-only exclude "status" which is used
> to enable or disable wakeup of the acpi device.
> 
> "acpi_bus_id" is acpi bus ID of the acpi device.
> 
> "bus_id" is pci bus id of the device associated to the acpi
> device, it will be empty if there isn't any device associated
> to it.
> 
> "pci_id" is PCI ID of the pci device associated to the acpi
> device, it will be empty if there isn't any device associated
> to it.
> 
> "run_wake" is a flag indicating if a wakeup process is being
> handled.
> 
> "sleep_state" is sleep state of the acpi device such as "S0".
> 
> "status" is wakeup status of the acpi device, it is enabled
> or disabled, a user can change it be echoing "0", "1",
> "disabled" or "enabled" to /sys/devices/.../wakeup/status. 
> 
> Here is the test result:
> 
> [root@localhost ~]# cat /proc/acpi/wakeup
> Device  S-state   Status   Sysfs node           PCI ID
> C093      S5     disabled  pci:0000:00:1e.0     0x2448
> C0E8      S3     disabled  pci:0000:00:1d.0     0x27c8
> C0EF      S3     disabled  pci:0000:00:1d.1     0x27c9
> C0F0      S3     disabled  pci:0000:00:1d.2     0x27ca
> C0F1      S3     disabled  pci:0000:00:1d.3     0x27cb
> C0F2      S3     disabled  pci:0000:00:1d.7     0x27cc
> C0F9      S0     disabled  pci:0000:00:1c.0     0x27d0
> C21D      S0     disabled  pci:0000:08:00.0     0x16fd
> C109      S5     disabled  pci:0000:00:1c.1     0x27d2
> C228      S5     disabled  pci:0000:10:00.0     0x4222
> C10F      S5     disabled  pci:0000:00:1c.3     0x27d6
> C229      S5     disabled
> [root@localhost ~]# find /sys -name "*" | grep sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:05/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:0d/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:11/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:15/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:19/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:1d/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2b/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2b/device:2c/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2d/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2d/device:2e/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/wakeup/sleep_state
> /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/sleep_state
> [root@localhost ~]# ls /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup
> acpi_bus_id  bus_id  pci_id  run_wakeup  sleep_state  status
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/acpi_bus_id
> cat: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/acpi_bus_id: No such file or directory
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/acpi_bus_id
> C229
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/sleep_state
> S5
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/status
> disabled
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/bus_id
> 
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/pci_id
> 
> [root@localhost ~]# echo 1 > /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/status
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:2f/device:30/wakeup/status
> enabled
> [root@localhost ~]# cat /proc/acpi/wakeup
> Device  S-state   Status   Sysfs node           PCI ID
> C093      S5     disabled  pci:0000:00:1e.0     0x2448
> C0E8      S3     disabled  pci:0000:00:1d.0     0x27c8
> C0EF      S3     disabled  pci:0000:00:1d.1     0x27c9
> C0F0      S3     disabled  pci:0000:00:1d.2     0x27ca
> C0F1      S3     disabled  pci:0000:00:1d.3     0x27cb
> C0F2      S3     disabled  pci:0000:00:1d.7     0x27cc
> C0F9      S0     enabled   pci:0000:00:1c.0     0x27d0
> C21D      S0     enabled   pci:0000:08:00.0     0x16fd
> C109      S5     enabled   pci:0000:00:1c.1     0x27d2
> C228      S5     enabled   pci:0000:10:00.0     0x4222
> C10F      S5     enabled   pci:0000:00:1c.3     0x27d6
> C229      S5     enabled
> [root@localhost ~]# vi /var/log/dmesg
> [root@localhost ~]# dmesg | grep "same GPE"
> ACPI: 'C0F9' and 'C229' have the same GPE, can't disable/enable one seperately
> ACPI: 'C21D' and 'C229' have the same GPE, can't disable/enable one seperately
> ACPI: 'C109' and 'C229' have the same GPE, can't disable/enable one seperately
> ACPI: 'C228' and 'C229' have the same GPE, can't disable/enable one seperately
> ACPI: 'C10F' and 'C229' have the same GPE, can't disable/enable one seperately
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/*/wakeup/status
> disabled
> disabled
> disabled
> disabled
> disabled
> disabled
> enabled
> enabled
> enabled
> [root@localhost ~]# cat /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/*/*/wakeup/status
> enabled
> enabled
> enabled
> [root@localhost ~]#


I think that it would be much much better to place wake-up attributes under
corresponding PCI and PNP devices.

Probably it is even better to link this code to PCI code, so PCI drivers will be aware of ACPI.
For example it will fix the 'EHCI instantly wakes up the system from S4' on my system, since here USB doesn't wake
up anything from S4, and ACPI tables correctly show that.

If ehci driver was aware of that it could disable #PME on entrance to S4.
And we even can reuse its 'wakeup' attribute, thus enabling wakeup automatically.

Going ever further, I think that it will be great to get rid of ACPI device tree, since
most acpi devices are ether PCI of PNP ones.

Or, even better have a small ACPI tree, that will contain 'true' ACPI devices, like cpus
thermal sensors, buttons, etc. 

Best regards,
	Maxim Levitsky
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