From 897b842296f1285a6b58e9170f7017022e2e2603 Mon Sep 17 00:00:00 2001 From: Chris Pascoe Date: Sun, 2 Dec 2007 09:39:18 -0300 Subject: [PATCH] V4L/DVB (6854): xc2028: be more specific about when applying offset for 7MHz channels We have been inserting a mystery 500kHz offset for tuning 7MHz channels, however some experimentation reveals it is only needed under certain conditions with specific firmware combinations. Document these and only apply the offset when we know it is required. Signed-off-by: Chris Pascoe Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/tuner-xc2028.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/media/video/tuner-xc2028.c b/drivers/media/video/tuner-xc2028.c index a6b05dfd6703..63a6fca1f8cf 100644 --- a/drivers/media/video/tuner-xc2028.c +++ b/drivers/media/video/tuner-xc2028.c @@ -875,7 +875,16 @@ static int generic_set_freq(struct dvb_frontend *fe, u32 freq /* in HZ */, rc = send_seq(priv, {0x00, 0x00}); } else { offset = 2750000; - if (priv->cur_fw.type & DTV7) + /* + * We must adjust the offset by 500kHz in two cases in order + * to correctly center the IF output: + * 1) When the ZARLINK456 or DIBCOM52 tables were explicitly + * selected and a 7MHz channel is tuned; + * 2) When tuning a VHF channel with DTV78 firmware. + */ + if (((priv->cur_fw.type & DTV7) && + (priv->cur_fw.scode_table & (ZARLINK456 | DIBCOM52))) || + ((priv->cur_fw.type & DTV78) && freq < 470000000)) offset -= 500000; }