[patch 01/56] ACPI: dock: Dont eval _STA on every show_docked sysfs read

Greg KH
2009-02-11T00:28:19Z

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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------

From: Holger Macht <hmacht@suse.de>

commit fc5a9f8841ee87d93376ada5d73117d4d6a373ea upstream.

Some devices trigger a DEVICE_CHECK on every evalutation of _STA. This
can also be seen in commit 8b59560a3baf2e7c24e0fb92ea5d09eca92805db
(ACPI: dock: avoid check _STA method). If an undock is processed, the
dock driver sends a uevent and userspace might read the show_docked
property in sysfs. This causes an evaluation of _STA of the particular
device which causes the dock driver to immediately dock again.

In any case, evaluation of _STA (show_docked) does not necessarily mean
that we are docked, so check with the internal device structure.

http://bugzilla.kernel.org/show_bug.cgi?id=12360

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/acpi/dock.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -691,8 +691,14 @@ fdd_out:
static ssize_t show_docked(struct device *dev,
struct device_attribute *attr, char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station));
+ struct acpi_device *tmp;

+ struct dock_station *dock_station = *((struct dock_station **)
+ dev->platform_data);
+
+ if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp)))
+ return snprintf(buf, PAGE_SIZE, "1\n");
+ return snprintf(buf, PAGE_SIZE, "0\n");
}
static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);