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

Zhang Rui
2007-04-06T09:38:14Z

On Thu, 2007-04-05 at 03:58 -0700, David Brownell wrote:
> On Thursday 05 April 2007 12:59 am, Zhang Rui wrote:
> > On Wed, 2007-04-04 at 08:41 +0800, David Brownell wrote:
> > > In that example, two devices don't actually exist (USB3, S139), one can't
> > > issue wakeup events (PCI0), and two seem harmlessly (?) confused (MDM and
> > > AUD are the same PCI device, but it's the _modem_ that does wake-on-ring).
> > >
> > Well, ACPI can't find the sysfs node for all the wakeup-enabled devices.
>
> The only example of that type in the example I provided is SLPB, where the
> sysfs node is ACPI-internal; I'm not sure how one can detect such cases.
>
>
> > In fact, only pci and pnp devices can be found now.
>
> Well, PNP courtesy of a previous patch from me, but remember that I was
> using that as an example of a ** BOGUS ACPI TABLE ** as summarized above.
Then it's OK. :)
>
> > ACPI needs the ability to distinguish all the physical devices, i.e. map
> > ACPI device to physical device nodes in sysfs, which I mentioned before.
>
> For wakeup devices, the main issue I've seen is with button devices.
> In my limited set of test sytems, everything else is either PCI, PNP,
> or a bug (listing a non-existent device).
There may be other wakeup-enabled devices like legacy serial,
PS2 devices described in ACPI name space.
> If this patch starts to get deployed, I expect other people will find
> a few other curiousities ... and likely some things to be fixed.

> The /sys/devices/acpi_system:00/ tree is kind of new. I suspect one
> way it could be more informative is to set up cross-links in sysfs
> between the ACPI devices and the "real" device nodes ... e.g. on the
> system I'm using right now .../device:00/PNP0A03:00/device:15/PNP0B00:00
> could have a link pointing to /sys/devices/pnp0/00:06 ... and that PNP
> node in turn could have an "acpi" link pointing back to the ACPI thing.
>
> Such cross-links would let people see those relationships, and observe
> which links are missing or otherwise strange. Fixing the bugs would
> seem unlikely until those things become visible.
Sounds nice.
The patch below should make sense.

Add cross-links between ACPI device and "real" devices in sysfs.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
drivers/acpi/glue.c | 14 ++++++++++++++
1 files changed, 14 insertions(+)

Index: linux-2.6.21-rc5/drivers/acpi/glue.c
===================================================================
--- linux-2.6.21-rc5.orig/drivers/acpi/glue.c 2007-04-06 16:06:04.000000000 +0800
+++ linux-2.6.21-rc5/drivers/acpi/glue.c 2007-04-06 17:32:40.000000000 +0800
@@ -147,6 +147,7 @@ EXPORT_SYMBOL(acpi_get_physical_device);
static int acpi_bind_one(struct device *dev, acpi_handle handle)
{
acpi_status status;
+ struct acpi_device *acpi_dev;

if (dev->archdata.acpi_handle) {
printk(KERN_WARNING PREFIX
@@ -161,16 +162,29 @@ static int acpi_bind_one(struct device *
}
dev->archdata.acpi_handle = handle;

+ if (!acpi_bus_get_device(handle, &acpi_dev)) {
+ sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj, "ACPI_node");
+ sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj, "physical_node");
+ }
+
return 0;
}

static int acpi_unbind_one(struct device *dev)
{
+ struct acpi_device *acpi_dev;
+
if (!dev->archdata.acpi_handle)
return 0;
if (dev == acpi_get_physical_device(dev->archdata.acpi_handle)) {
/* acpi_get_physical_device increase refcnt by one */
put_device(dev);
+
+ if (!acpi_bus_get_device(dev->archdata.acpi_handle, &acpi_dev)) {
+ sysfs_remove_link(&dev->kobj, "ACPI_node");
+ sysfs_remove_link(&acpi_dev->dev.kobj, "physical_node");
+ }
+
acpi_detach_data(dev->archdata.acpi_handle,
acpi_glue_data_handler);
dev->archdata.acpi_handle = NULL;