From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mout.gmx.net ([212.227.15.18]:49855 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753052AbbH2PDR (ORCPT ); Sat, 29 Aug 2015 11:03:17 -0400 Subject: Re: [PATCH] stv090x: use lookup tables for carrier/noise ratio To: Mauro Carvalho Chehab References: <5238E030.8040203@gmx.de> <20141111082838.05369439@recife.lan> Cc: linux-media From: Joerg Riechardt Message-ID: <55E1C9A1.6040702@gmx.de> Date: Sat, 29 Aug 2015 17:02:57 +0200 MIME-Version: 1.0 In-Reply-To: <20141111082838.05369439@recife.lan> Content-Type: multipart/mixed; boundary="------------040806060509000808050105" Sender: linux-media-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------040806060509000808050105 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Am 11.11.2014 um 11:28 schrieb Mauro Carvalho Chehab: > Em Wed, 18 Sep 2013 01:05:20 +0200 > Joerg Riechardt escreveu: > >> The stv090x driver uses the lookup table for signal strength already, >> with this patch we use the lookup tables for carrier/noise ratio as well. >> This has the advantage, that values for DVB-S and DVB-S2 are now >> corresponding, while before they were way off. The values are now >> proportional to real carrier/noise ratio, while before they were >> corresponding to register values. So now applications are able to give >> the user real carrier/noise ratio. >> >> Because the output has to be within 0x0000...0xFFFF the three negative >> values for DVB-S2 are omitted. This is no significant loss, because >> reception is lost at 7.5 dB already (TT S2-1600, Cine S2), so the >> negative values are not really important, and also for DVB-S they don´t >> exist. >> >> Signed-off-by: Joerg Riechardt >> >> Regards, >> Joerg >> >> --- stv090x.c.bak 2013-09-06 20:59:01.132365872 +0200 >> +++ stv090x.c 2013-09-10 03:21:48.884115191 +0200 >> @@ -173,9 +173,9 @@ >> >> /* DVBS2 C/N Lookup table */ >> static const struct stv090x_tab stv090x_s2cn_tab[] = { >> - { -30, 13348 }, /* -3.0dB */ >> - { -20, 12640 }, /* -2d.0B */ >> - { -10, 11883 }, /* -1.0dB */ >> +// { -30, 13348 }, /* -3.0dB */ >> +// { -20, 12640 }, /* -2d.0B */ >> +// { -10, 11883 }, /* -1.0dB */ >> { 0, 11101 }, /* -0.0dB */ >> { 5, 10718 }, /* 0.5dB */ >> { 10, 10339 }, /* 1.0dB */ > > Instead of commenting, just truncate the value at the DVBv3 stats > function. Ok, done. Changed patch attached. > >> @@ -3697,9 +3697,10 @@ >> } >> val /= 16; >> last = ARRAY_SIZE(stv090x_s2cn_tab) - 1; >> - div = stv090x_s2cn_tab[0].read - >> - stv090x_s2cn_tab[last].read; >> - *cnr = 0xFFFF - ((val * 0xFFFF) / div); >> + div = stv090x_s2cn_tab[last].real - >> + stv090x_s2cn_tab[0].real; >> + val = stv090x_table_lookup(stv090x_s2cn_tab, last, val); >> + *cnr = val * 0xFFFF / div; >> } >> break; >> >> @@ -3719,9 +3720,10 @@ >> } >> val /= 16; >> last = ARRAY_SIZE(stv090x_s1cn_tab) - 1; >> - div = stv090x_s1cn_tab[0].read - >> - stv090x_s1cn_tab[last].read; >> - *cnr = 0xFFFF - ((val * 0xFFFF) / div); >> + div = stv090x_s1cn_tab[last].real - >> + stv090x_s1cn_tab[0].real; >> + val = stv090x_table_lookup(stv090x_s1cn_tab, last, val); >> + *cnr = val * 0xFFFF / div; >> } > > As, with this patch, C/N will be a properly scaled value, the best > is to add support for DVBv5 stats. With DVBv5 stats, the scale can > be sent to userspace. Sorry, I have no plans to add DVBv5 stats, although I agree, it would be nice, if someone did. Signed-off-by: Joerg Riechardt Regards, Joerg > >> break; >> default: > > Regards, > Mauro > --------------040806060509000808050105 Content-Type: text/plain; charset=UTF-8; name="stv090x-use-lookup-tables-for-carrier-noise-ratio.v2.patch" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename*0="stv090x-use-lookup-tables-for-carrier-noise-ratio.v2.patch" ZGlmZiAtTnJ1IEEvc3R2MDkweC5jIEIvc3R2MDkweC5jCi0tLSBBL3N0djA5MHguYwkyMDE1 LTA2LTI1IDE0OjMzOjU4LjAwMDAwMDAwMCArMDIwMAorKysgQi9zdHYwOTB4LmMJMjAxNS0w OC0yOSAxNjowNzo0NC44ODk4NjEyMzAgKzAyMDAKQEAgLTM3MjYsOSArMzcyNiwxMiBAQAog CQkJfQogCQkJdmFsIC89IDE2OwogCQkJbGFzdCA9IEFSUkFZX1NJWkUoc3R2MDkweF9zMmNu X3RhYikgLSAxOwotCQkJZGl2ID0gc3R2MDkweF9zMmNuX3RhYlswXS5yZWFkIC0KLQkJCSAg ICAgIHN0djA5MHhfczJjbl90YWJbbGFzdF0ucmVhZDsKLQkJCSpjbnIgPSAweEZGRkYgLSAo KHZhbCAqIDB4RkZGRikgLyBkaXYpOworCQkJZGl2ID0gc3R2MDkweF9zMmNuX3RhYltsYXN0 XS5yZWFsIC0KKwkJCSAgICAgIHN0djA5MHhfczJjbl90YWJbM10ucmVhbDsKKwkJCXZhbCA9 IHN0djA5MHhfdGFibGVfbG9va3VwKHN0djA5MHhfczJjbl90YWIsIGxhc3QsIHZhbCk7CisJ CQlpZiAodmFsIDwgMCkKKwkJCQl2YWwgPSAwOworCQkJKmNuciA9IHZhbCAqIDB4RkZGRiAv IGRpdjsKIAkJfQogCQlicmVhazsKIApAQCAtMzc0OCw5ICszNzUxLDEwIEBACiAJCQl9CiAJ CQl2YWwgLz0gMTY7CiAJCQlsYXN0ID0gQVJSQVlfU0laRShzdHYwOTB4X3MxY25fdGFiKSAt IDE7Ci0JCQlkaXYgPSBzdHYwOTB4X3MxY25fdGFiWzBdLnJlYWQgLQotCQkJICAgICAgc3R2 MDkweF9zMWNuX3RhYltsYXN0XS5yZWFkOwotCQkJKmNuciA9IDB4RkZGRiAtICgodmFsICog MHhGRkZGKSAvIGRpdik7CisJCQlkaXYgPSBzdHYwOTB4X3MxY25fdGFiW2xhc3RdLnJlYWwg LQorCQkJICAgICAgc3R2MDkweF9zMWNuX3RhYlswXS5yZWFsOworCQkJdmFsID0gc3R2MDkw eF90YWJsZV9sb29rdXAoc3R2MDkweF9zMWNuX3RhYiwgbGFzdCwgdmFsKTsKKwkJCSpjbnIg PSB2YWwgKiAweEZGRkYgLyBkaXY7CiAJCX0KIAkJYnJlYWs7CiAJZGVmYXVsdDoK --------------040806060509000808050105--