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authorLan Tianyu <tianyu.lan@intel.com>2014-11-23 21:22:54 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-11-24 01:04:55 +0100
commit40e7fcb19293cbdff02c74cb0668413480f82ea1 (patch)
tree05e1c91e4f3b06bf4234d0ac1014acdf4757766b /drivers/acpi/battery.c
parent5d01410fe4d92081f349b013a2e7a95429e4f2c9 (diff)
ACPI: Add _DEP support to fix battery issue on Asus T100TA
ACPI 5.0 introduces _DEP (Operation Region Dependencies) to designate device objects that OSPM should assign a higher priority in start ordering due to future operation region accesses. On Asus T100TA, ACPI battery info are read from a I2C slave device via I2C operation region. Before I2C operation region handler is installed, battery _STA always returns 0. There is a _DEP method of designating start order under battery device node. This patch is to implement _DEP feature to fix battery issue on the Asus T100TA. Introducing acpi_dep_list and adding dep_unmet count in struct acpi_device. During ACPI namespace scan, create struct acpi_dep_data for a valid pair of master (device pointed to by _DEP)/ slave(device with _DEP), record master's and slave's ACPI handle in it and put it into acpi_dep_list. The dep_unmet count will increase by one if there is a device under its _DEP. Driver's probe() should return EPROBE_DEFER when find dep_unmet is larger than 0. When I2C operation region handler is installed, remove all struct acpi_dep_data on the acpi_dep_list whose master is pointed to I2C host controller and decrease slave's dep_unmet. When dep_unmet decreases to 0, all _DEP conditions are met and then do acpi_bus_attach() for the device in order to resolve battery _STA issue on the Asus T100TA. Link: https://bugzilla.kernel.org/show_bug.cgi?id=69011 Tested-by: Jan-Michael Brummer <jan.brummer@tabos.org> Tested-by: Adam Williamson <adamw@happyassassin.net> Tested-by: Michael Shigorin <shigorin@gmail.com> Acked-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/battery.c')
-rw-r--r--drivers/acpi/battery.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 8ec8a89a20ab..d98ba4355819 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -1180,6 +1180,10 @@ static int acpi_battery_add(struct acpi_device *device)
if (!device)
return -EINVAL;
+
+ if (device->dep_unmet)
+ return -EPROBE_DEFER;
+
battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
if (!battery)
return -ENOMEM;