From e3b87f8a9d5a61f6367c66d1bb0a4e19d251194d Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 21 Sep 2009 19:30:11 +0000 Subject: [PATCH] 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 Signed-off-by: Len Brown --- drivers/acpi/scan.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 954bd01f295a..2c4cac576a7e 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)) { -- 2.20.1