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authorBjorn Helgaas <bjorn.helgaas@hp.com>2009-09-21 19:30:11 +0000
committerLen Brown <len.brown@intel.com>2009-09-25 14:24:32 -0400
commite3b87f8a9d5a61f6367c66d1bb0a4e19d251194d (patch)
tree9054b93f90f9de3b536f656727c947c1d34b4519
parent778cbc1d3abd434b6d882714630235e3711bb15b (diff)
downloadlinux-linaro-e3b87f8a9d5a61f6367c66d1bb0a4e19d251194d.tar.gz
ACPI: handle re-enumeration, when acpi_devices might already exist
acpi_bus_scan() traverses the namespace to enumerate devices and uses acpi_add_single_object() to create acpi_devices. When the platform notifies us of a hot-plug event, we need to traverse part of the namespace again to figure out what appeared or disappeared. (We don't yet call acpi_bus_scan() during hot-plug, but I plan to do that in the future.) This patch makes acpi_add_single_object() notice when we already have an acpi_device, so we don't need to make a new one. Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Len Brown <len.brown@intel.com>
-rw-r--r--drivers/acpi/scan.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 954bd01f295..2c4cac576a7 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1400,10 +1400,10 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
void *context, void **return_value)
{
struct acpi_bus_ops *ops = context;
- struct acpi_device *device = NULL;
- acpi_status status;
int type;
unsigned long long sta;
+ struct acpi_device *device;
+ acpi_status status;
int result;
result = acpi_bus_type_and_status(handle, &type, &sta);
@@ -1414,13 +1414,16 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
!(sta & ACPI_STA_DEVICE_FUNCTIONING))
return AE_CTRL_DEPTH;
- if (ops->acpi_op_add)
- status = acpi_add_single_object(&device, handle, type, sta,
- ops);
- else
- status = acpi_bus_get_device(handle, &device);
+ /*
+ * We may already have an acpi_device from a previous enumeration. If
+ * so, we needn't add it again, but we may still have to start it.
+ */
+ device = NULL;
+ acpi_bus_get_device(handle, &device);
+ if (ops->acpi_op_add && !device)
+ acpi_add_single_object(&device, handle, type, sta, ops);
- if (ACPI_FAILURE(status))
+ if (!device)
return AE_CTRL_DEPTH;
if (ops->acpi_op_start && !(ops->acpi_op_add)) {