Subject: [PATCH] [acpi video] Add helper for getting a device's EDID

- Add video_dev_edid() that returns a buffer and a size
- Add get_buffer() helper that gets a buffer from the namespace

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

---

 drivers/acpi/drivers/video/dev-device.c |   51 +++++++++++++++++++++++++++++++
 drivers/acpi/drivers/video/video.h      |    1 +
 2 files changed, 52 insertions(+), 0 deletions(-)

applies-to: 1bcce000434df10653d3b0efb3456d5b09d090bc
57e52cf4e80832a9959b4895ae6ebd459fe7cfd2
diff --git a/drivers/acpi/drivers/video/dev-device.c b/drivers/acpi/drivers/video/dev-device.c
index 66b0591..658d080 100644
--- a/drivers/acpi/drivers/video/dev-device.c
+++ b/drivers/acpi/drivers/video/dev-device.c
@@ -88,6 +88,38 @@ static int get_int_array(struct acpi_dev
 	return 0;
 }
 
+static int get_buffer(struct acpi_dev * ad, char * method, 
+		      size_t ask_len, char ** buffer, size_t * len)
+{
+	union acpi_object arg = {
+		.type		= ACPI_TYPE_INTEGER,
+		.integer	= {
+			.value	= ask_len,
+		},
+	};
+	struct acpi_object_list arg_list = {
+		.count		= 1,
+		.pointer	= &arg,
+	};
+	struct acpi_buffer ab = {
+		.length		= ACPI_ALLOCATE_BUFFER,
+	};
+	acpi_status status;
+
+	status = acpi_evaluate_object(ad->acpi_device->handle, method,
+				      &arg_list, &ab);
+	if (ACPI_SUCCESS(status)) {
+		union acpi_object * obj = ab.pointer;
+
+		if (obj && obj->type == ACPI_TYPE_BUFFER) {
+			*len = obj->buffer.length;
+			*buffer = obj->buffer.pointer;
+			return 0;
+		}
+	}
+	return -ENODEV;
+}
+
 /**
  *	video_dev_test - Determine whether this is a video device
  *	@ad:	The ACPI device that we're testing
@@ -185,3 +217,22 @@ const char * video_dev_string(struct acp
 	}
 	return str;
 }
+
+
+int video_dev_edid(struct acpi_video_dev * vd, char ** buffer, size_t * len)
+{
+	int ret;
+
+	/*
+	 * First try for 128 bytes
+	 */
+	ret = get_buffer(vd->v_ad, "_DDC", 1, buffer, len);
+	if (ret) {
+		/*
+		 * No love, so try 256
+		 */
+		ret = get_buffer(vd->v_ad, "_DDC", 2, buffer, len);
+	}
+	return ret;
+}
+
diff --git a/drivers/acpi/drivers/video/video.h b/drivers/acpi/drivers/video/video.h
index aedd495..58504c1 100644
--- a/drivers/acpi/drivers/video/video.h
+++ b/drivers/acpi/drivers/video/video.h
@@ -70,6 +70,7 @@ struct acpi_video_dev {
 extern int video_dev_test(struct acpi_dev * ad);
 extern int video_dev_init(struct acpi_video_dev * vd);
 extern const char * video_dev_string(struct acpi_video_dev * vd);
+extern int video_dev_edid(struct acpi_video_dev * vd, char ** buffer, size_t * len);
 
 extern int video_bus_attach(struct acpi_video_dev * vd);
 extern void video_bus_detach(struct acpi_video_dev * vd);
---
0.99.9.GIT