the pointer we give to audio_fill_silence() may point in the middle of a

sample (eg. if write(2) have written an odd number of bytes and 16bit
encoding is used), so we'll not properly write silence. To fix this,
round start pointer to fill with silence uncomplete samples too.

ok jakemsr@

1 files changed, 23 insertions, 13 deletions

diff --git a/sys/dev/audio.c b/sys/dev/audio.c
index fa5819223e0..ef4dd0503cb 100644
--- a/sys/dev/audio.c
+++ b/sys/dev/audio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: audio.c,v 1.86 2007/10/27 08:52:47 ratchov Exp $	*/
+/*	$OpenBSD: audio.c,v 1.87 2007/10/28 13:23:01 ratchov Exp $	*/
 /*	$NetBSD: audio.c,v 1.119 1999/11/09 16:50:47 augustss Exp $	*/
 
 /*
@@ -129,7 +129,7 @@ int	audio_check_params(struct audio_params *);
 
 void	audio_set_blksize(struct audio_softc *, int, int);
 void	audio_calc_blksize(struct audio_softc *, int);
-void	audio_fill_silence(struct audio_params *, u_char *, int);
+void	audio_fill_silence(struct audio_params *, u_char *, u_char *, int);
 int	audio_silence_copyout(struct audio_softc *, int, struct uio *);
 
 void	audio_init_ringbuffer(struct audio_ringbuffer *);
@@ -1066,10 +1066,10 @@ audio_drain(struct audio_softc *sc)
 		cc = cb->blksize - (inp - cb->start) % cb->blksize;
 		if (sc->sc_pparams.sw_code) {
 			int ncc = cc / sc->sc_pparams.factor;
-			audio_fill_silence(&sc->sc_pparams, inp, ncc);
+			audio_fill_silence(&sc->sc_pparams, cb->start, inp, ncc);
 			sc->sc_pparams.sw_code(sc->hw_hdl, inp, ncc);
 		} else
-			audio_fill_silence(&sc->sc_pparams, inp, cc);
+			audio_fill_silence(&sc->sc_pparams, cb->start, inp, cc);
 		inp += cc;
 		if (inp >= cb->end)
 			inp = cb->start;
@@ -1342,11 +1342,21 @@ audio_calc_blksize(struct audio_softc *sc, int mode)
 }
 
 void
-audio_fill_silence(struct audio_params *params, u_char *p, int n)
+audio_fill_silence(struct audio_params *params, u_char *start, u_char *p, int n)
 {
+	size_t rounderr;
 	u_char auzero0, auzero1 = 0; /* initialize to please gcc */
 	int nfill = 1;
 
+	/*
+	 * p may point the middle of a sample; round it to the
+	 * beginning of the sample, so we overwrite partially written
+	 * ones.
+	 */
+	rounderr = (p - start) % (params->precision / 8);
+	p -= rounderr;
+	n += rounderr;
+
 	switch (params->encoding) {
 	case AUDIO_ENCODING_ULAW:
 		auzero0 = 0x7f;
@@ -1403,7 +1413,7 @@ audio_silence_copyout(struct audio_softc *sc, int n, struct uio *uio)
 	int k;
 	u_char zerobuf[128];
 
-	audio_fill_silence(&sc->sc_rparams, zerobuf, sizeof zerobuf);
+	audio_fill_silence(&sc->sc_rparams, zerobuf, zerobuf, sizeof zerobuf);
 
 	error = 0;
 	while (n > 0 && uio->uio_resid > 0 && !error) {
@@ -1568,10 +1578,10 @@ audio_write(dev_t dev, struct uio *uio, int ioflag)
 			DPRINTFN(1, ("audio_write: fill %d\n", cc));
 			if (sc->sc_pparams.sw_code) {
 				int ncc = cc / sc->sc_pparams.factor;
-				audio_fill_silence(&sc->sc_pparams, einp, ncc);
+				audio_fill_silence(&sc->sc_pparams, cb->start, einp, ncc);
 				sc->sc_pparams.sw_code(sc->hw_hdl, einp, ncc);
 			} else
-				audio_fill_silence(&sc->sc_pparams, einp, cc);
+				audio_fill_silence(&sc->sc_pparams, cb->start, einp, cc);
 		}
 	}
 	return (error);
@@ -1859,7 +1869,7 @@ audio_mmap(dev_t dev, off_t off, int prot)
 	if (!cb->mmapped) {
 		cb->mmapped = 1;
 		if (cb == &sc->sc_pr) {
-			audio_fill_silence(&sc->sc_pparams, cb->start, cb->bufsize);
+			audio_fill_silence(&sc->sc_pparams, cb->start, cb->start, cb->bufsize);
 			s = splaudio();
 			if (!sc->sc_pbus && !sc->sc_pr.pause)
 				(void)audiostartp(sc);
@@ -1963,10 +1973,10 @@ audio_pint_silence(struct audio_softc *sc, struct audio_ringbuffer *cb,
 
 			if (sc->sc_pparams.sw_code) {
 				int ncc = cc / sc->sc_pparams.factor;
-				audio_fill_silence(&sc->sc_pparams, inp, ncc);
+				audio_fill_silence(&sc->sc_pparams, cb->start, inp, ncc);
 				sc->sc_pparams.sw_code(sc->hw_hdl, inp, ncc);
 			} else
-				audio_fill_silence(&sc->sc_pparams, inp, cc);
+				audio_fill_silence(&sc->sc_pparams, cb->start, inp, cc);
 
 		} else {
 			DPRINTFN(5, ("audio_pint_silence: already silent cc=%d inp=%p\n", cc, inp));
@@ -1980,10 +1990,10 @@ audio_pint_silence(struct audio_softc *sc, struct audio_ringbuffer *cb,
 
 		if (sc->sc_pparams.sw_code) {
 			int ncc = cc / sc->sc_pparams.factor;
-			audio_fill_silence(&sc->sc_pparams, inp, ncc);
+			audio_fill_silence(&sc->sc_pparams, cb->start, inp, ncc);
 			sc->sc_pparams.sw_code(sc->hw_hdl, inp, ncc);
 		} else
-			audio_fill_silence(&sc->sc_pparams, inp, cc);
+			audio_fill_silence(&sc->sc_pparams, cb->start, inp, cc);
 
 	}
 }