Subject: [PATCH] [acpi video] Add ability to probe for video bus devices

- Add helper is_handle() for determining whether or not a named method
  exists in the device's namespace.
- Add video_bus_test() for checking whether or not a particular device
  is a real video device.
- Call from video_probe() in driver.c.

Signed-off-by: Patrick Mochel <mochel@linux.intel.com>

---

 drivers/acpi/drivers/video/device.c |   57 +++++++++++++++++++++++++++++++++++
 drivers/acpi/drivers/video/driver.c |    6 ++++
 drivers/acpi/drivers/video/video.h  |    3 +-
 3 files changed, 64 insertions(+), 2 deletions(-)

applies-to: 724fae855e48e7022a6b163cc9a11881235c01e5
6517cae822b7b8376d47c115b7413e22cb2f9c88
diff --git a/drivers/acpi/drivers/video/device.c b/drivers/acpi/drivers/video/device.c
index 79f8a67..7a11dda 100644
--- a/drivers/acpi/drivers/video/device.c
+++ b/drivers/acpi/drivers/video/device.c
@@ -11,3 +11,60 @@
  */
 
 #include "video.h"
+
+
+/**
+ *	is_handle - Check if a named object exists in the namespace
+ *	@ad:	The ACPI device whose namespace we're checking
+ *	@obj:	The name of the handle to check for
+ *
+ */
+
+static int is_handle(struct acpi_dev * ad, char * obj)
+{
+	acpi_handle h;
+	acpi_status status;
+
+	status = acpi_get_handle(ad->acpi_device->handle, obj, &h);
+	return ACPI_SUCCESS(status) ? 1 : 0;
+}
+
+
+/**
+ *	video_bus_test - Check device to see if it's a video bus
+ *	@ad:	The ACPI device that we're checking
+ *
+ *	Since there is no HID or CID for ACPI Video devices, we have
+ *	to check well known required nodes for each feature we support.
+ *
+ *	We bind to a device if it supports one of the following:
+ *	- Video switching (via _DOD or _DOS)
+ *	- Retrieving video ROM (via _ROM)
+ *	- Ability to configure head to be POSTed (via _VPD, _GPD and _SPD)
+ *
+ *	Returns %1 if the device is a video device; %0 otherwise.
+ */
+
+int video_bus_test(struct acpi_dev * ad)
+{
+	/*
+	 * Video switching
+	 */
+	if (is_handle(ad, "_DOD") && is_handle(ad, "_DOS"))
+		return 1;
+
+	/*
+	 * ROM retrieval
+	 */
+	if (is_handle(ad, "_ROM"))
+		return 1;
+
+	/*
+	 * POST configuration
+	 */
+	if (is_handle(ad, "_VPD") && 
+	    is_handle(ad, "_GPD") &&
+	    is_handle(ad, "_SPD"))
+		return 1;
+	return 0;
+}
diff --git a/drivers/acpi/drivers/video/driver.c b/drivers/acpi/drivers/video/driver.c
index 0311ca9..10f2825 100644
--- a/drivers/acpi/drivers/video/driver.c
+++ b/drivers/acpi/drivers/video/driver.c
@@ -12,6 +12,11 @@
 
 #include "video.h"
 
+static int video_probe(struct acpi_dev * ad)
+{
+	return video_bus_test(ad);
+}
+
 static int video_add(struct acpi_dev * ad)
 {
 	struct acpi_video * av;
@@ -38,6 +43,7 @@ static int video_remove(struct acpi_dev 
 	return 0;
 }
 
+
 acpi_no_start(video);
 acpi_no_stop(video);
 acpi_no_shutdown(video);
diff --git a/drivers/acpi/drivers/video/video.h b/drivers/acpi/drivers/video/video.h
index 57dea68..1e1ea01 100644
--- a/drivers/acpi/drivers/video/video.h
+++ b/drivers/acpi/drivers/video/video.h
@@ -16,5 +16,4 @@ struct acpi_video {
 	struct acpi_dev		* v_ad;
 };
 
-extern int video_get_state(struct acpi_video * av);
-extern int video_set_state(struct acpi_video * av, unsigned int state);
+extern int video_bus_test(struct acpi_dev * ad);
---
0.99.9.GIT