[PATCH v2 3/4] media: v4l: Add a module parameter to control global debugging

[Ezequiel Garcia <ezequiel@collabora.com>]

In addition to the dev_debug device attribute, which controls
per-device debugging, we now add a module parameter to control
debugging globally.

This will allow to add debugging of v4l2 control logic,
using the newly introduced debug parameter.

In addition, this module parameter adds consistency to the
subsystem, since other v4l2 modules expose the same parameter.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
---
 drivers/media/v4l2-core/v4l2-dev.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 7cfb05204065..39d22bfbe420 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -36,8 +36,16 @@
 #define VIDEO_NUM_DEVICES	256
 #define VIDEO_NAME              "video4linux"
 
+unsigned int videodev_debug;
+module_param_named(debug, videodev_debug, uint, 0644);
+
+/*
+ * The videodev_debug module parameter controls the global debug level,
+ * while the dev_debug device attribute controls the local
+ * per-device debug level.
+ */
 #define dprintk(vdev, flags, fmt, arg...) do {				\
-	if (vdev->dev_debug & flags)					\
+	if ((videodev_debug & flags) || (vdev->dev_debug & flags))	\
 		printk(KERN_DEBUG pr_fmt("%s: %s: " fmt),		\
 		       __func__, video_device_node_name(vdev), ##arg);	\
 } while (0)
-- 
2.20.1