From 30b54d50f6e2b8f5a4c8b5ade3d25a02612f8f51 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil@xs4all.nl>
Date: Mon, 9 Jan 2006 15:25:43 -0200
Subject: [PATCH] V4L/DVB (3254): Don't reprogram the video standard if it is
unchanged.
- Don't reprogram the video standard if the new standard
equals the old standard.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
---
drivers/media/video/saa7115.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/media/video/saa7115.c b/drivers/media/video/saa7115.c
index 3e4e5584c5d0..5d33d0922e79 100644
--- a/drivers/media/video/saa7115.c
+++ b/drivers/media/video/saa7115.c
@@ -668,6 +668,16 @@ static void saa7115_set_v4lstd(struct i2c_client *client, v4l2_std_id std)
struct saa7115_state *state = i2c_get_clientdata(client);
int taskb = saa7115_read(client, 0x80) & 0x10;
+ /* Prevent unnecessary standard changes. During a standard
+ change the I-Port is temporarily disabled. Any devices
+ reading from that port can get confused.
+ Note that VIDIOC_S_STD is also used to switch from
+ radio to TV mode, so if a VIDIOC_S_STD is broadcast to
+ all I2C devices then you do not want to have an unwanted
+ side-effect here. */
+ if (std == state->std)
+ return;
+
// This works for NTSC-M, SECAM-L and the 50Hz PAL variants.
if (std & V4L2_STD_525_60) {
saa7115_dbg("decoder set standard 60 Hz\n");
--
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