[src/trunk]: src/sys/dev Independent blocksizes for virtual channels where a ...

[nat <nat%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2d6b6717daf8
branches:  trunk
changeset: 827406:2d6b6717daf8
user:      nat <nat%NetBSD.org@localhost>
date:      Fri Oct 27 01:34:32 2017 +0000

description:
Independent blocksizes for virtual channels where a static blocksize is
not stipulated by the underlying hw driver.

This improves latency in games esp. when the stream format differs from
the harware format.

OK christos@.

diffstat:

 sys/dev/audio.c |  63 ++++++++++++++++++++++++++++++++++++--------------------
 1 files changed, 40 insertions(+), 23 deletions(-)

diffs (105 lines):

diff -r 4b9a4b8a2da0 -r 2d6b6717daf8 sys/dev/audio.c
--- a/sys/dev/audio.c   Fri Oct 27 00:55:27 2017 +0000
+++ b/sys/dev/audio.c   Fri Oct 27 01:34:32 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.416 2017/10/26 22:45:00 nat Exp $  */
+/*     $NetBSD: audio.c,v 1.417 2017/10/27 01:34:32 nat Exp $  */
 
 /*-
  * Copyright (c) 2016 Nathanial Sloss <nathanialsloss%yahoo.com.au@localhost>
@@ -148,7 +148,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.416 2017/10/26 22:45:00 nat Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.417 2017/10/27 01:34:32 nat Exp $");
 
 #ifdef _KERNEL_OPT
 #include "audio.h"
@@ -276,6 +276,8 @@
 int    mix_read(void *);
 int    audio_check_params(struct audio_params *);
 
+static void    audio_setblksize(struct audio_softc *,
+                                struct virtual_channel *, int, int);
 int    audio_calc_blksize(struct audio_softc *, const audio_params_t *);
 void   audio_fill_silence(const struct audio_params *, uint8_t *, int);
 int    audio_silence_copyout(struct audio_softc *, int, struct uio *);
@@ -2221,9 +2223,6 @@
                mode |= AUMODE_PLAY | AUMODE_PLAY_ALL;
        }
 
-       vc->sc_mpr.blksize = sc->sc_mixring.sc_mpr.blksize;
-       vc->sc_mrr.blksize = sc->sc_mixring.sc_mrr.blksize;
-
        /*
         * Multiplex device: /dev/audio (MU-Law) and /dev/sound (linear)
         * The /dev/audio is always (re)set to 8-bit MU-Law mono
@@ -2641,6 +2640,38 @@
        mutex_exit(sc->sc_intr_lock);
 }
 
+static void
+audio_setblksize(struct audio_softc *sc, struct virtual_channel *vc,
+    int blksize, int mode)
+{
+       struct audio_ringbuffer *mixcb, *cb;
+       audio_params_t *parm;
+       audio_stream_t *stream;
+
+       if (mode == AUMODE_RECORD) {
+               mixcb = &sc->sc_mixring.sc_mrr;
+               cb = &vc->sc_mrr;
+               parm = &vc->sc_rparams;
+               stream = vc->sc_rustream;
+       } else {
+               mixcb = &sc->sc_mixring.sc_mpr;
+               cb = &vc->sc_mpr;
+               parm = &vc->sc_pparams;
+               stream = vc->sc_pustream;
+       }
+
+       if (vc == sc->sc_hwvc) {
+               mixcb->blksize = audio_calc_blksize(sc, parm);
+               cb->blksize = audio_calc_blksize(sc, &cb->s.param);
+       } else {
+               if (SPECIFIED(blksize))
+                       cb->blksize = blksize;
+               else {
+                       cb->blksize = audio_calc_blksize(sc, &stream->param);
+               }
+       }
+}
+
 int
 audio_calc_blksize(struct audio_softc *sc, const audio_params_t *parm)
 {
@@ -4714,24 +4745,10 @@
                        audio_init_record(sc, vc);
        }
 
-       if (vc == sc->sc_hwvc) {
-               if (!cleared) {
-                       audio_clear_intr_unlocked(sc, vc);
-                       cleared = true;
-               }
-               if (nr > 0) {
-                       sc->sc_mixring.sc_mrr.blksize =
-                           audio_calc_blksize(sc, &vc->sc_rparams);
-                       vc->sc_mrr.blksize = audio_calc_blksize(sc,
-                           &vc->sc_mrr.s.param);
-               }
-               if (np > 0) {
-                       sc->sc_mixring.sc_mpr.blksize = audio_calc_blksize(sc,
-                           &vc->sc_pparams);
-                       vc->sc_mpr.blksize = audio_calc_blksize(sc,
-                           &vc->sc_mpr.s.param);
-               }
-       }
+       if (nr > 0)
+               audio_setblksize(sc, vc, ai->blocksize, AUMODE_RECORD);
+       if (np > 0)
+               audio_setblksize(sc, vc, ai->blocksize, AUMODE_PLAY);
 
        if (hw->commit_settings && sc->sc_opens + sc->sc_recopens == 0) {
                error = hw->commit_settings(sc->hw_hdl);