Date: Sun, 05 Nov 2000 23:26:57 +0100 From: Khamba Staring <purrcat@edoropolis.org> To: freebsd-multimedia@freebsd.org Subject: SB ViBRA16C 16bit recording problems ( + ugly fix?) Message-ID: <200011052227.eA5MQw617325@francine.edoropolis.org>
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Hi,
I'm experiencing some problems trying to record sound using a
SoundBlaster ViBRA16C under FreeBSD 4.1. Playback of 16 bits
audio works (haven't tried 8bit playback), but recording at
16 bits per sample does not work. Recording _did_ work when
I used FreeBSD 3.3 on the same machine (I recently made sure).
On both FreeBSD 3.3 and 4.1, I used the `newpcm' driver.
The card is properly detected and no drq conflicts are present..
-- (dmesg)
sbc1: <Creative ViBRA16C> at port 0x220-0x22f,0x330-0x331,0x388-0x38b
irq 5 drq 1,5 on isa0
sbc1: setting card to irq 5, drq 1, 5
--
I searched a bit through the /sys/dev/sound source files and
added some debugging printf()s. The driver seems to go through
sbchan_init twice (once for every drq i presume?).
It seems the `read end' got drq1 and the `write end' got drq5,
but 16bit recording needs drq5.. I base this presumption on what
I see in the function sbchan_init() in /sys/dev/sound/isa/sb.c :
-- (sb.c, I added two printf()s here)
dch = (dir == PCMDIR_PLAY)? 1 : 0;
if (sb->bd_flags & BD_F_SB16X)
dch = !dch;
dl = rman_get_start(sb->drq1);
dh = sb->drq2? rman_get_start(sb->drq2) : dl;
printf("SB sbchan_init1: ch->buffer->chan %d\n", ch->buffer->chan);
ch->buffer->chan = dch? dh : dl;
printf("SB sbchan_init2: ch->buffer->chan %d\n", ch->buffer->chan);
--
dch is only 1 if dir = PCMDIR_PLAY so if dir != PCMDIR, ch->buffer->chan
will always equal dl, the lower drq. Why is this done?
Evilly setting ch->buffer->chan to 5 (drq5) seems to work nicely and
playback still works (quickly tested it while typing this mail)..
Now I can't record 8bit, but I couldn't care less about that :)
Can anyone tell my why this is done?? I'm really puzzled..
Kind regards,
-- Khamba Staring
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