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authorHans Verkuil <hverkuil@xs4all.nl>2009-01-15 05:53:18 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-03-30 12:42:23 -0300
commit6ca187abb2fc1a52b2a8e0422f3ffce2e3bb7ad0 (patch)
treebd6720ce26a8eb2dd4a2038bb8d66c9a1b879172
parentc7d29e2f530654aa0c323aafb94d42a6a718482c (diff)
V4L/DVB (10251): cx25840: add comments explaining what the init() does.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
-rw-r--r--drivers/media/video/cx25840/cx25840-core.c10
-rw-r--r--include/media/cx25840.h12
2 files changed, 22 insertions, 0 deletions
diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c
index 25eb3bec9e5..be467b4b954 100644
--- a/drivers/media/video/cx25840/cx25840-core.c
+++ b/drivers/media/video/cx25840/cx25840-core.c
@@ -1101,6 +1101,16 @@ static void log_audio_status(struct i2c_client *client)
/* ----------------------------------------------------------------------- */
+/* This init operation must be called to load the driver's firmware.
+ Without this the audio standard detection will fail and you will
+ only get mono.
+
+ Since loading the firmware is often problematic when the driver is
+ compiled into the kernel I recommend postponing calling this function
+ until the first open of the video device. Another reason for
+ postponing it is that loading this firmware takes a long time (seconds)
+ due to the slow i2c bus speed. So it will speed up the boot process if
+ you can avoid loading the fw as long as the video device isn't used. */
static int cx25840_init(struct v4l2_subdev *sd, u32 val)
{
struct cx25840_state *state = to_state(sd);
diff --git a/include/media/cx25840.h b/include/media/cx25840.h
index db431d513f2..2c3fbaa33f7 100644
--- a/include/media/cx25840.h
+++ b/include/media/cx25840.h
@@ -21,6 +21,18 @@
#ifndef _CX25840_H_
#define _CX25840_H_
+/* Note that the cx25840 driver requires that the bridge driver calls the
+ v4l2_subdev's init operation in order to load the driver's firmware.
+ Without this the audio standard detection will fail and you will
+ only get mono.
+
+ Since loading the firmware is often problematic when the driver is
+ compiled into the kernel I recommend postponing calling this function
+ until the first open of the video device. Another reason for
+ postponing it is that loading this firmware takes a long time (seconds)
+ due to the slow i2c bus speed. So it will speed up the boot process if
+ you can avoid loading the fw as long as the video device isn't used. */
+
enum cx25840_video_input {
/* Composite video inputs In1-In8 */
CX25840_COMPOSITE1 = 1,