I saw this in the windows driver and thought I'd throw it in for
completeness, even though it makes no difference. When selecting a
video input, if the input is s-video, an additional i2c read/write is
done, explicitly setting
VGA_SEL_CH2=0
VGA_SEL_CH3=0
CHROMA_IN_SEL=1
The first two are also automatically set by AFE auto config I believe
(because I don't see anywhere where we set them to 0, but they somehow
magically flip when input goes to svideo), the third setting is the
default and is never changed.
So I don't know why the windows driver does it, but here is a patch that
mimics the same behavior. Feel free to discard it if you don't think it
will ever make a difference.
Something the windows driver does that we don't that I find odd is:
On input select, it does the standard SOFT_RESET, MICROCTRL off, but
then sets the audio path for tuner, and sets the audio PLLs up like it
is going to do tuner audio 48Khz. Then the input is changed to what it
should actually be, the sample rate is set properly, and then the
MICROCTRL is only restarted if going to tuner audio. This is in
contrast to the way we do it where we've got the microcontroller going
unless we're changing a setting. Is there any merit to either of these
operations?
Index: ivtv/driver/cx25840-driver.c
===================================================================
--- ivtv/driver/cx25840-driver.c (revision 271)
+++ ivtv/driver/cx25840-driver.c (working copy)
@@ -653,6 +653,9 @@
CX25840_SET_CH_3__SOURCE(0x0000);
CX25840_SET_CH_SEL_ADC2(0x0000);
CX25840_SET_INPUT_MODE(0x0001);
+ CX25840_SET_VGA_SEL_CH2(0x00);
+ CX25840_SET_VGA_SEL_CH3(0x00);
+ CX25840_SET_CHROMA_IN_SEL(0x01);
break;
case CX25840_TUNER:
