From 0edd7fd2bc7af1ac72f305dbb9d2f3a12a89dbcb Mon Sep 17 00:00:00 2001
From: Stefan Seyfried <seife@tuxbox-git.slipkontur.de>
Date: Sun, 3 Mar 2013 22:11:57 +0100
Subject: [PATCH] zapit: add delay when retrying SCR tuning

this is not exactly the algorithm as described in EN50494
sect.8, but rand() is probably good enough :-)
---
 src/zapit/src/scan.cpp  |  7 +++++--
 src/zapit/src/zapit.cpp | 13 ++++++++++---
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/zapit/src/scan.cpp b/src/zapit/src/scan.cpp
index 6129d5d2d..3c3614d2f 100644
--- a/src/zapit/src/scan.cpp
+++ b/src/zapit/src/scan.cpp
@@ -156,8 +156,11 @@ bool CServiceScan::tuneFrequency(FrontendParameters *feparams, uint8_t polarizat
 		if (abort_scan)
 			break;
 		retry--;
-		if (retry)
-			printf("[unicable] [scan] retrying tune, retry=%d\n", retry);
+		if (retry) {
+			int rand_us = (rand() * 1000000LL / RAND_MAX);
+			printf("[scan] SCR retrying tune, retry=%d after %dms\n", retry, rand_us/1000);
+			usleep(rand_us);
+		}
 	} while (retry > 0);
 	return false;
 }
diff --git a/src/zapit/src/zapit.cpp b/src/zapit/src/zapit.cpp
index 9db98d4bc..c22adefaf 100644
--- a/src/zapit/src/zapit.cpp
+++ b/src/zapit/src/zapit.cpp
@@ -511,8 +511,9 @@ bool CZapit::ZapIt(const t_channel_id channel_id, bool forupdate, bool startplay
 
 	live_channel_id = current_channel->getChannelID();
 	SaveSettings(false);
+	srand(time(NULL));
 
-	/* retry tuning twice when using unicable */
+	/* retry tuning twice when using unicable, TODO: EN50494 sect.8 specifies 4 retries... */
 	int retry = (live_fe->getDiseqcType() == DISEQC_UNICABLE) * 2;
  again:
 	if(!TuneChannel(live_fe, newchannel, transponder_change)) {
@@ -521,7 +522,11 @@ bool CZapit::ZapIt(const t_channel_id channel_id, bool forupdate, bool startplay
 			SendEvent(CZapitClient::EVT_TUNE_COMPLETE, &chid, sizeof(t_channel_id));
 			return false;
 		}
-		printf("[zapit] %s:1 unicable retry tuning %d\n", __func__, retry);
+		int rand_us = (rand() * 1000000LL / RAND_MAX); /* max. 1 second delay */
+		printf("[zapit] %s:1 SCR retry tuning %d after %dms\n", __func__, retry, rand_us / 1000);
+		/* EN50494 sect.8 specifies an elaborated way of calculating the delay, but I'm
+		 * pretty sure rand() is not much worse :-) */
+		usleep(rand_us);
 		live_fe->tuned = false;
 		retry--;
 		goto again;
@@ -536,7 +541,9 @@ bool CZapit::ZapIt(const t_channel_id channel_id, bool forupdate, bool startplay
 	failed = !ParsePatPmt(current_channel);
 
 	if (failed && retry > 0) {
-		printf("[zapit] %s:2 unicable retry tuning %d\n", __func__, retry);
+		int rand_us = (rand() * 1000000LL / RAND_MAX);
+		printf("[zapit] %s:2 SCR retry tuning %d after %dms\n", __func__, retry, rand_us / 1000);
+		usleep(rand_us);
 		live_fe->tuned = false;
 		retry--;
 		goto again;