Merged revisions 278618 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r278618 | mmichelson | 2010-07-22 09:55:04 -0500 (Thu, 22 Jul 2010) | 13 lines
  
  Allow PLC to function properly when channels use SLIN for audio.
  
  If a channel involved in a bridge was using SLIN audio, then translation
  paths were not guaranteed to be set up properly since in all likelihood
  the number of translation steps was only 1.
  
  This patch enforces the transcode_via_slin behavior if transcode_via_slin
  or generic_plc is enabled and one of the formats to make compatible is
  SLIN.
  
  AST-352
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@278620 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -5418,6 +5418,7 @@ int ast_channel_sendurl(struct ast_channel *chan, const char *url)
 static int ast_channel_make_compatible_helper(struct ast_channel *from, struct ast_channel *to)
 {
 	format_t src, dst;
+	int use_slin;
 
 	/* See if the channel driver can natively make these two channels compatible */
 	if (from->tech->bridge && from->tech->bridge == to->tech->bridge &&
@@ -5449,8 +5450,9 @@ static int ast_channel_make_compatible_helper(struct ast_channel *from, struct a
 	 * no direct conversion available. If generic PLC is
 	 * desired, then transcoding via SLINEAR is a requirement
 	 */
+	use_slin = (src == AST_FORMAT_SLINEAR || dst == AST_FORMAT_SLINEAR);
 	if ((src != dst) && (ast_opt_generic_plc || ast_opt_transcode_via_slin) &&
-	    (ast_translate_path_steps(dst, src) != 1))
+	    (ast_translate_path_steps(dst, src) != 1 || use_slin))
 		dst = AST_FORMAT_SLINEAR;
 	if (ast_set_read_format(from, dst) < 0) {
 		ast_log(LOG_WARNING, "Unable to set read format on channel %s to %s\n", from->name, ast_getformatname(dst));