From 859ac9a4be0c753cece0e30a2e4a65fd2cdcaeee Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 21 Sep 2009 19:29:50 +0000 Subject: ACPI: identify device tree root by null parent pointer, not ACPI_BUS_TYPE We can identify the root of the ACPI device tree by the fact that it has no parent. This is simpler than passing around ACPI_BUS_TYPE_SYSTEM and will help remove special treatment of the device tree root. Currently, we add the root by hand with ACPI_BUS_TYPE_SYSTEM. If we traverse the tree treating the root as just another device and use acpi_get_type(), the root shows up as ACPI_TYPE_DEVICE. Signed-off-by: Bjorn Helgaas Signed-off-by: Len Brown --- drivers/acpi/scan.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 27d2dec55c6c..0b5aaf059c9b 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -22,6 +22,8 @@ extern struct acpi_device *acpi_root; #define ACPI_BUS_HID "LNXSYBUS" #define ACPI_BUS_DEVICE_NAME "System Bus" +#define ACPI_IS_ROOT_DEVICE(device) (!(device)->parent) + static LIST_HEAD(acpi_device_list); static LIST_HEAD(acpi_bus_id_list); DEFINE_MUTEX(acpi_device_lock); @@ -955,10 +957,12 @@ static void acpi_device_get_busid(struct acpi_device *device) * The device's Bus ID is simply the object name. * TBD: Shouldn't this value be unique (within the ACPI namespace)? */ - switch (device->device_type) { - case ACPI_BUS_TYPE_SYSTEM: + if (ACPI_IS_ROOT_DEVICE(device)) { strcpy(device->pnp.bus_id, "ACPI"); - break; + return; + } + + switch (device->device_type) { case ACPI_BUS_TYPE_POWER_BUTTON: strcpy(device->pnp.bus_id, "PWRF"); break; @@ -1093,6 +1097,11 @@ static void acpi_device_set_id(struct acpi_device *device) switch (device->device_type) { case ACPI_BUS_TYPE_DEVICE: + if (ACPI_IS_ROOT_DEVICE(device)) { + hid = ACPI_SYSTEM_HID; + break; + } + status = acpi_get_object_info(device->handle, &info); if (ACPI_FAILURE(status)) { printk(KERN_ERR PREFIX "%s: Error reading device info\n", __func__); @@ -1129,9 +1138,6 @@ static void acpi_device_set_id(struct acpi_device *device) case ACPI_BUS_TYPE_PROCESSOR: hid = ACPI_PROCESSOR_OBJECT_HID; break; - case ACPI_BUS_TYPE_SYSTEM: - hid = ACPI_SYSTEM_HID; - break; case ACPI_BUS_TYPE_THERMAL: hid = ACPI_THERMAL_HID; break; @@ -1643,7 +1649,7 @@ int __init acpi_scan_init(void) * Create the root device in the bus's device tree */ result = acpi_add_single_object(&acpi_root, ACPI_ROOT_OBJECT, - ACPI_BUS_TYPE_SYSTEM, &ops); + ACPI_BUS_TYPE_DEVICE, &ops); if (result) goto Done; -- cgit v1.2.1