diff options
| author | Marc Espie <espie@cvs.openbsd.org> | 2001-09-05 08:29:56 +0000 |
|---|---|---|
| committer | Marc Espie <espie@cvs.openbsd.org> | 2001-09-05 08:29:56 +0000 |
| commit | 0eba55045bf3dc8f137469181ce091e0716b098a (patch) | |
| tree | 1d366820a5258d3658fe3a31783fef0d841a074c /sys/dev/pci | |
| parent | 8c6b9f6eb559ab3faeba98d7f24ce33cc02b60ed (diff) | |
Stereo jitter suppressor.
Idea from FreeBSD.
This code was not put in initially because I had no problematic
card to test.
Thanks to Chris Kuethe <ckuethe@pyxis.cns.ualberta.ca> for having
such a card and testing this code.
Diffstat (limited to 'sys/dev/pci')
| -rw-r--r-- | sys/dev/pci/maestro.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/sys/dev/pci/maestro.c b/sys/dev/pci/maestro.c index 7eff62c1b22..f42ef208645 100644 --- a/sys/dev/pci/maestro.c +++ b/sys/dev/pci/maestro.c @@ -1,4 +1,4 @@ -/* $OpenBSD: maestro.c,v 1.9 2001/08/25 10:13:29 art Exp $ */ +/* $OpenBSD: maestro.c,v 1.10 2001/09/05 08:29:55 espie Exp $ */ /* $FreeBSD: /c/ncvs/src/sys/dev/sound/pci/maestro.c,v 1.3 2000/11/21 12:22:11 julian Exp $ */ /* * FreeBSD's ESS Agogo/Maestro driver @@ -202,6 +202,7 @@ void maestro_powerhook __P((int, void *)); void maestro_channel_start __P((struct maestro_channel *)); void maestro_channel_stop __P((struct maestro_channel *)); void maestro_channel_advance_dma __P((struct maestro_channel *)); +void maestro_channel_suppress_jitter __P((struct maestro_channel *)); int maestro_get_flags __P((struct pci_attach_args *)); @@ -1285,6 +1286,22 @@ maestro_channel_advance_dma(ch) #endif } +/* Some maestro makes sometimes get desynchronized in stereo mode. */ +void +maestro_channel_suppress_jitter(ch) + struct maestro_channel *ch; +{ + int cp, diff; + + /* Verify that both channels are not too far off. */ + cp = wp_apu_read(ch->sc, ch->num, APUREG_CURPTR); + diff = wp_apu_read(ch->sc, ch->num+1, APUREG_CURPTR) - cp; + if (diff > 4 || diff < -4) + /* Otherwise, directly resynch the 2nd channel. */ + bus_space_write_2(ch->sc->iot, ch->sc->ioh, + PORT_DSP_DATA, cp); +} + /* ----------------------------- * Interrupt handler interface */ @@ -1342,9 +1359,11 @@ maestro_intr(arg) MIDDLE_VOLUME); } - if (sc->play.mode & MAESTRO_RUNNING) + if (sc->play.mode & MAESTRO_RUNNING) { maestro_channel_advance_dma(&sc->play); - /* XXX suppress jitter for stereo play? */ + if (sc->play.mode & MAESTRO_STEREO) + maestro_channel_suppress_jitter(&sc->play); + } if (sc->record.mode & MAESTRO_RUNNING) maestro_channel_advance_dma(&sc->record); |