From e4dc3ba0e1ca66ed5fa7aab8d55e8518d1610aa2 Mon Sep 17 00:00:00 2001
From: Stefan Pluecken <stefan.pluecken@multimedia-labs.de>
Date: Mon, 5 Jul 2010 16:12:08 +0200
Subject: [PATCH] add snr calculations for CXD1981 frontend

---
 lib/dvb/frontend.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/dvb/frontend.cpp b/lib/dvb/frontend.cpp
index a1ba8fe5..abbb8d29 100644
--- a/lib/dvb/frontend.cpp
+++ b/lib/dvb/frontend.cpp
@@ -906,6 +906,19 @@ int eDVBFrontend::readFrontendData(int type)
 			}
 			else if (strstr(m_description, "BCM4506") || strstr(m_description, "BCM4505"))
 				ret = (snr * 100) >> 8;
+			else if (!strcmp(m_description, "CXD1981"))
+			{
+				int mse = (~snr) & 0xFF;
+				switch (parm_u_qam_modulation) {
+					case QAM_16:
+					case QAM_64:
+					case QAM_256: ret = (int)(-950 * log(((double)mse) / 760)); break;
+					case QAM_32:
+					case QAM_128: ret = (int)(-875 * log(((double)mse) / 650)); break;
+
+					default: break;
+				}
+			}
 
 			if (type == signalQuality)
 			{
-- 
2.30.2