From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout4.w2.samsung.com ([211.189.100.14]:35100 "EHLO usmailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752205AbaGVQLH (ORCPT ); Tue, 22 Jul 2014 12:11:07 -0400 Received: from uscpsbgm1.samsung.com (u114.gpu85.samsung.co.kr [203.254.195.114]) by usmailout4.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N9400L7RFMGGK60@usmailout4.samsung.com> for linux-media@vger.kernel.org; Tue, 22 Jul 2014 12:11:04 -0400 (EDT) Date: Tue, 22 Jul 2014 13:10:59 -0300 From: Mauro Carvalho Chehab To: Luis Alves Cc: linux-media@vger.kernel.org, crope@iki.fi Subject: Re: [PATCH] si2157: Fix DVB-C bandwidth. Message-id: <20140722131059.4ad26777.m.chehab@samsung.com> In-reply-to: <1406027388-10336-1-git-send-email-ljalvs@gmail.com> References: <1406027388-10336-1-git-send-email-ljalvs@gmail.com> MIME-version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Em Tue, 22 Jul 2014 12:09:48 +0100 Luis Alves escreveu: > This patch fixes DVB-C reception. > Without setting the bandwidth to 8MHz the received stream gets corrupted. > > Regards, > Luis > > Signed-off-by: Luis Alves > --- > drivers/media/tuners/si2157.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c > index 6c53edb..e2de428 100644 > --- a/drivers/media/tuners/si2157.c > +++ b/drivers/media/tuners/si2157.c > @@ -245,6 +245,7 @@ static int si2157_set_params(struct dvb_frontend *fe) > break; > case SYS_DVBC_ANNEX_A: > delivery_system = 0x30; > + bandwidth = 0x08; Hmm... this patch looks wrong, as it will break DVB-C support where the bandwidth is lower than 6MHz. The DVB core sets c->bandwidth_hz for DVB-C based on the rolloff and the symbol rate. If this is not working for you, then something else is likely wrong. I suggest you to add a printk() there to show what's the value set at c->bandwidth_hz and what's the symbol rate that you're using. On DVB-C, the rolloff is fixed (1.15 for annex A and 1.13 for Annex C). Not sure if DVB-C2 allows selecting a different rolloff factor, nor if si2157 works with DVB-C2. > break; > default: > ret = -EINVAL;