From aac840d9f91c52a1dc3dcbdbfc3c628a80a717a1 Mon Sep 17 00:00:00 2001
From: Alexandre Ratchov <alex@caoua.org>
Date: Tue, 15 Jun 2021 17:15:24 +0200
Subject: [PATCH] oss: Fix sio_setpar() when channel number is not set

The trap value set by sio_initpar() was interpreted as a channel
number, causing sio_setpar() to fail.

Found and analysed by Roman Bogorodskiy <bogorodskiy at gmail.com>,
thanks
---
 libsndio/sio_oss.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libsndio/sio_oss.c b/libsndio/sio_oss.c
index 6a171c1..22c37fc 100644
--- a/libsndio/sio_oss.c
+++ b/libsndio/sio_oss.c
@@ -436,9 +436,9 @@ sio_oss_setpar(struct sio_hdl *sh, struct sio_par *par)
 	if (hdl->rate > 192000)
 		hdl->rate = 192000;
 
-	if (hdl->sio.mode & SIO_PLAY)
+	if ((hdl->sio.mode & SIO_PLAY) && par->pchan != ~0U)
 		hdl->chan = par->pchan;
-	else if (hdl->sio.mode & SIO_REC)
+	else if ((hdl->sio.mode & SIO_REC) && par->rchan != ~0U)
 		hdl->chan = par->rchan;
 
 	if (ioctl(hdl->fd, SNDCTL_DSP_SETFMT, &hdl->fmt) == -1) {