ACPI battery: only refresh the sysfs files when pertinent information changes (Closes: #670958)

svn path=/dists/sid/linux-2.6/; revision=19019

debian/changelog

@@ -28,6 +28,8 @@ linux-2.6 (3.2.18-1) UNRELEASED; urgency=low
   * [x86] KVM: VMX: vmx_set_cr0 expects kvm->srcu locked
   * [s390] KVM: do store status after handling STOP_ON_STOP bit
   * [s390] KVM: Sanitize fpc registers for KVM_SET_FPU
+  * ACPI battery: only refresh the sysfs files when pertinent information
+    changes (Closes: #670958)
 
  -- Ben Hutchings <ben@decadent.org.uk>  Wed, 16 May 2012 02:19:30 +0100
 

debian/patches/bugfix/all/acpi-battery-only-refresh-the-sysfs-files-when-pertinent.patch

@@ -0,0 +1,49 @@
+From: Andy Whitcroft <apw@canonical.com>
+Date: Thu, 3 May 2012 14:48:26 +0100
+Subject: ACPI battery: only refresh the sysfs files when pertinent
+ information changes
+
+commit c5971456964290da7e98222892797b71ef793e62 upstream.
+
+We only need to regenerate the sysfs files when the capacity units
+change, avoid the update otherwise.
+
+The origin of this issue is dates way back to 2.6.38:
+da8aeb92d4853f37e281f11fddf61f9c7d84c3cd
+(ACPI / Battery: Update information on info notification and resume)
+
+Signed-off-by: Andy Whitcroft <apw@canonical.com>
+Tested-by: Ralf Jung <post@ralfj.de>
+Signed-off-by: Len Brown <len.brown@intel.com>
+---
+ drivers/acpi/battery.c |   10 +++++++++-
+ 1 file changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
+index 86933ca..7dd3f9f 100644
+--- a/drivers/acpi/battery.c
++++ b/drivers/acpi/battery.c
+@@ -643,11 +643,19 @@ static int acpi_battery_update(struct acpi_battery *battery)
+ 
+ static void acpi_battery_refresh(struct acpi_battery *battery)
+ {
++	int power_unit;
++
+ 	if (!battery->bat.dev)
+ 		return;
+ 
++	power_unit = battery->power_unit;
++
+ 	acpi_battery_get_info(battery);
+-	/* The battery may have changed its reporting units. */
++
++	if (power_unit == battery->power_unit)
++		return;
++
++	/* The battery has changed its reporting units. */
+ 	sysfs_remove_battery(battery);
+ 	sysfs_add_battery(battery);
+ }
+-- 
+1.7.10
+

debian/patches/series/base

@@ -229,3 +229,5 @@
 # Add support for Ralink RT5392/RF5372 chipset
 + features/all/rt2x00-add-debug-message-for-new-chipset.patch
 + features/all/rt2x00-add-rt5372-chipset-support.patch
+
++ bugfix/all/acpi-battery-only-refresh-the-sysfs-files-when-pertinent.patch