wavrec(1) cannot record from the second time on half-duplex mode

[Watanabe Kazuhiro]

Hi, everyone.

When I try to record with wavrec (a part of ports/audio/wavplay) on
half-duplex mode, cannot record from the second time.  At the first
time it works correctly.

I've tested other recording software.  Rec (ports/audio/sox) and
rawrec (ports/audio/rawrec) is no problem at least.


 * Environment (FreeBSD-current: CVSup'ed Dec. 7)

$ uname -a
FreeBSD scorpio.zodiac.org 7.0-CURRENT FreeBSD 7.0-CURRENT #8: Wed Dec  7 21:36:50 JST 2005     nabe at scorpio.zodiac.org:/FreeBSD/obj-current/FreeBSD/FreeBSD-current/src/sys/GENERIC  i386
$ cat /dev/sndstat
FreeBSD Audio Driver (newpcm)
Installed devices:
pcm0: <Avance Logic ALS4000> at io 0xe800 irq 9 kld snd_als4000 (1p/1r/0v channels duplex default)
pcm1: <SB16 DSP 4.13> at io 0x240 irq 5 drq 1:5 bufsz 4096 kld snd_sb16 (1p/1r/0v channels duplex)
pcm2: <CS423x> at io 0x534 irq 10 drq 3:0 bufsz 4096 (1p/1r/0v channels duplex)
$

 * Case 1 (full-duplex mode, works fine)

$ grep sbc /boot/device.hints
hint.sbc.0.at="isa"
hint.sbc.0.port="0x240"
hint.sbc.0.irq="5"
hint.sbc.0.drq="1"
hint.sbc.0.flags="0x15"
$ cat /dev/sndstat | grep pcm1
pcm1: <SB16 DSP 4.13> at io 0x240 irq 5 drq 1:5 bufsz 4096 kld snd_sb16 (1p/1r/0v channels duplex)
$ time wavrec -d /dev/dsp1 -S -s 44100 -b 16 -t 10 test.wav 
       10.07 real         0.02 user         1.18 sys
$ time wavrec -d /dev/dsp1 -S -s 44100 -b 16 -t 10 test.wav
       10.07 real         0.01 user         1.19 sys
$ ls -l test.wav
-rw-r--r--  1 nabe  nabe  1764044 Dec  9 21:23 test.wav
$

 * Case 2 (half-duplex mode, works only once)

$ grep sbc /boot/device.hints
hint.sbc.0.at="isa"
hint.sbc.0.port="0x240"
hint.sbc.0.irq="5"
hint.sbc.0.drq="1"
hint.sbc.0.flags="0"
$ cat /dev/sndstat | grep pcm1
pcm1: <SB16 DSP 4.13> at io 0x240 irq 5 drq 1 bufsz 4096 kld snd_sb16 (1p/1r/0v channels)
$ time wavrec -d /dev/dsp1 -S -s 44100 -b 16 -t 10 test.wav 
       10.15 real         0.00 user         1.19 sys
$ time wavrec -d /dev/dsp1 -S -s 44100 -b 16 -t 10 test.wav
Device busy:
Opening audio device /dev/dsp1
        1.60 real         0.00 user         1.59 sys
$ ls -l test.wav
-rw-r--r--  1 nabe  nabe  44 Dec  9 21:30 test.wav
$

In case 2, there is a LOR message on the console.  The LOR message is
below:

lock order reversal:
 1st 0xc22e8640 pcm1 (sound cdev) @ /FreeBSD/FreeBSD-current/src/sys/modules/sound/sound/../../../dev/sound/pcm/dsp.c:277
 2nd 0xc22e85e0 pcm1:record:0 (pcm record channel) @ /FreeBSD/FreeBSD-current/src/sys/modules/sound/sound/../../../dev/sound/pcm/dsp.c:290
KDB: stack backtrace:
kdb_backtrace(0,ffffffff,c0954ff0,c0954f78,c08e27a4) at kdb_backtrace+0x29
witness_checkorder(c22e85e0,9,c0ac7b63,122) at witness_checkorder+0x580
_mtx_lock_flags(c22e85e0,0,c0ac7b63,122,1) at _mtx_lock_flags+0x5b
dsp_open(c22f8800,3,2000,c25ffd80,c094614c) at dsp_open+0x2fd
giant_open(c22f8800,3,2000,c25ffd80,c22f8800) at giant_open+0x30
devfs_open(d1398a08) at devfs_open+0x223
VOP_OPEN_APV(c08db0c0,d1398a08) at VOP_OPEN_APV+0x7e
vn_open_cred(d1398b70,d1398c70,0,c260b100,4) at vn_open_cred+0x3fe
vn_open(d1398b70,d1398c70,0,4,6b2) at vn_open+0x1e
kern_open(c25ffd80,bfbfed76,0,3,0) at kern_open+0xb6
open(c25ffd80,d1398d04,c,c25ffd80,d1398d30) at open+0x1a
syscall(3b,3b,3b,805204c,8051000) at syscall+0x27e
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (5, FreeBSD ELF32, open), eip = 0x2811fb5f, esp = 0xbfbfeadc, ebp = 0xbfbfeb08 ---


Wavrec open a sound device (default: /dev/audio) with O_RDWR flag.
Probably it's wrong.  Because wavrec doesn't support full-duplex
operation.

It is documented in "Open Sound System(TM) Programmer's Guide" pp29:
| It is recommended that the device file is opened in read only
| (O_RDONLY) or write only (O_WRONLY) mode.  Read write mode (O_RDWR)
| should be used only when it is necessary to record and play back at
| the same time (full duplex mode).
("Selecting and Opening the Sound Device"
 http://www.opensound.com/pguide/oss.pdf)

Actually, this problem can be fixed by the patch:
--- recplay.c.configured        Fri Dec  9 21:47:01 2005
+++ recplay.c   Fri Dec  9 21:50:53 2005
@@ -190,7 +190,7 @@
                wfile = svr.wfile;              /* And the file is already opened */
        }
 
-       if ( (dfile = OpenDSP(wfile,O_RDWR,v_erf)) == NULL )
+       if ( (dfile = OpenDSP(wfile,O_RDONLY,v_erf)) == NULL )
                goto errxit;
 
        if ( RecordDSP(dfile,wfile,samples,svr_work_proc,v_erf) )


Is it an only wavrec's bug?  If so, I will send-pr.

If it's a newpcm's bug, please somebody fix the problem...
In FreeBSD/pc98, most of PC-98 have an on-board MSS chip (CS4231A).
These are only works on half-duplex mode (single DRQ).  And
SoundBlaster16 for PC-98 is also worked on half-duplex too.
---
Watanabe Kazuhiro (CQG00620 at nifty.ne.jp)