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authorBjorn Helgaas <bjorn.helgaas@hp.com>2009-09-21 13:35:14 -0600
committerLen Brown <len.brown@intel.com>2009-09-25 14:26:02 -0400
commitb1fbfb2ae8f2f0e04219218da6f52f7313466899 (patch)
treef038ea487be82ccd96c21f143cdded80b0e52c12 /drivers/acpi
parentea8d82fd316208bd0ffe6f64823d04bcb8c57158 (diff)
downloadlinux-b1fbfb2ae8f2f0e04219218da6f52f7313466899.tar.gz
ACPI: make sure every acpi_device has an ID
This makes sure every acpi_device has at least one ID.  If we build an
acpi_device for a namespace node with no _HID or _CID, we sometimes
synthesize an ID like "LNXCPU" or "LNXVIDEO".  If we don't even have
that, give it a default "device" ID.

Note that this means things like:
    /sys/devices/LNXSYSTM:00/LNXSYBUS:00/HWP0001:00/HWP0002:04/device:00
(a PCI slot SxFy device) will have "hid" and "modprobe" entries, where
they didn't before.  These aren't very useful (a HID of "device" doesn't
tell you what *kind* of device it is, so it doesn't help find a driver),
but I don't think they're harmful.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/scan.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 269c0aae4bed..53b96e7a64ab 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1155,6 +1155,16 @@ static void acpi_device_set_id(struct acpi_device *device)
 		break;
 	}
 
+	/*
+	 * We build acpi_devices for some objects that don't have _HID or _CID,
+	 * e.g., PCI bridges and slots.  Drivers can't bind to these objects,
+	 * but we do use them indirectly by traversing the acpi_device tree.
+	 * This generic ID isn't useful for driver binding, but it provides
+	 * the useful property that "every acpi_device has an ID."
+	 */
+	if (!hid && !cid_list && !cid_add)
+		hid = "device";
+
 	if (hid) {
 		device->pnp.hardware_id = ACPI_ALLOCATE_ZEROED(strlen (hid) + 1);
 		if (device->pnp.hardware_id) {