Modular sound oddity

Nix (nix-kernel@esperi.demon.co.uk)
24 Jan 1999 16:37:49 +0000


I've just made the grand switch from 2.0.36 to 2.2.0pre9, and, well,
modular sound sample output seems a little interference-filled under
certain circumstances, to say the least.

This is (as the .config below will show) on an SB-AWE32 system (with
no RAM onboard as it happens, but that shouldn't affect simple sample
output via /dev/dsp).

It doesn't exhibit itself if you try a simple dd from /dev/zero to
/dev/dsp, but if you cat, for instance, the `linux-english.au' file
that's floating about the place to /dev/dsp, it's instantly observable
- well, audible; the sound is just about audible behind an ocean of
crackles and squeaks (which do not seem to be CPU-load dependent).

This behaviour is not evidenced in 2.0.36 (which means *nothing*
because the sound subsystem has changed so much :) )

The activated parts of my .config are attached below, with the sound
bits split out at the bottom.

My /etc/conf.modules looks like

alias net-pf-4 off
alias net-pf-5 off
alias sound sb
alias midi awe_wave
options sb io=0x220 irq=5 dma=1 dma16=5 mpu_io=0x330

My list of loaded modules looks like this when the sounds are playing:

sb 30684 0
uart401 5588 0 (autoclean) [sb]
sound 54524 0 (autoclean) [sb uart401]
soundlow 208 0 (autoclean) [sound]
soundcore 2084 6 (autoclean) [sb sound]
nls_cp437 3548 2 (autoclean)

(sb.c was loaded by kmod when the rplayd kicked itself up as the
system booted.)

/proc/sound looks like this:

OSS/Free:3.8s2++-971130
Load type: Driver loaded as a module
Kernel: Linux loki 2.2.0-final #1 Sun Jan 24 15:09:34 GMT 1999 i586
Config options: 0

Installed drivers:

Card config:

Audio devices:
0: Sound Blaster 16 (4.13) (DUPLEX)

Synth devices:

Midi devices:
0: Sound Blaster 16

Timers:
0: System clock

Mixers:
0: Sound Blaster

I've tried this with the kernel configured below built with both
gcc-2.7.2.3 and egcs-1.1.1, and the same problem occurs in both of
them. (This is on an i586-pc-linux-gnu box btw, running
glibc-2.0.7pre6, not that I expect this latter affects much. It's
fairly hard to break cat(1)...)

My .config's enabled bits look like this:

CONFIG_EXPERIMENTAL=y
CONFIG_M586TSC=y
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_TSC=y
CONFIG_MODULES=y
CONFIG_KMOD=y
CONFIG_NET=y
CONFIG_PCI=y
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_QUIRKS=y
CONFIG_SYSVIPC=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_SYSCTL=y
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_MISC=y
CONFIG_PARPORT=m
CONFIG_PARPORT_PC=m
CONFIG_APM=y
CONFIG_APM_POWER_OFF=y
CONFIG_APM_RTC_IS_GMT=y
CONFIG_BLK_DEV_FD=y
CONFIG_BLK_DEV_LOOP=m
CONFIG_PARIDE_PARPORT=m
CONFIG_PACKET=m
CONFIG_NETLINK=y
CONFIG_RTNETLINK=y
CONFIG_UNIX=y
CONFIG_INET=y
CONFIG_SYN_COOKIES=y
CONFIG_IP_NOSR=y
CONFIG_SKB_LARGE=y
CONFIG_SCSI=y
CONFIG_BLK_DEV_SD=y
CONFIG_BLK_DEV_SR=y
CONFIG_CHR_DEV_SG=y
CONFIG_SCSI_MULTI_LUN=y
CONFIG_SCSI_CONSTANTS=y
CONFIG_SCSI_NCR53C8XX=y
CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS=8
CONFIG_SCSI_NCR53C8XX_MAX_TAGS=32
CONFIG_SCSI_NCR53C8XX_SYNC=20
CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT=y
CONFIG_NETDEVICES=y
CONFIG_DUMMY=m
CONFIG_NET_ETHERNET=y
CONFIG_NET_VENDOR_3COM=y
CONFIG_VORTEX=y
CONFIG_PLIP=m
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_SERIAL=y
CONFIG_MOUSE=y
CONFIG_PSMOUSE=y
CONFIG_RTC=y
CONFIG_JOYSTICK=m
CONFIG_JOY_ANALOG=m
CONFIG_QUOTA=y
CONFIG_FAT_FS=y
CONFIG_MSDOS_FS=y
CONFIG_UMSDOS_FS=m
CONFIG_VFAT_FS=m
CONFIG_ISO9660_FS=y
CONFIG_MINIX_FS=m
CONFIG_PROC_FS=y
CONFIG_EXT2_FS=y
CONFIG_NFS_FS=y
CONFIG_SUNRPC=y
CONFIG_LOCKD=y
CONFIG_NLS=y
CONFIG_NLS_CODEPAGE_437=m
CONFIG_NLS_CODEPAGE_850=m
CONFIG_NLS_CODEPAGE_852=m
CONFIG_NLS_ISO8859_1=m
CONFIG_NLS_ISO8859_2=m
CONFIG_VGA_CONSOLE=y
CONFIG_VIDEO_SELECT=y

CONFIG_SOUND=m
CONFIG_SOUND_OSS=m
CONFIG_SOUND_SB=m
CONFIG_SOUND_ADLIB=m
CONFIG_SOUND_YM3812=m
CONFIG_LOWLEVEL_SOUND=y
CONFIG_AWE32_SYNTH=m

-- 
`Anyone who says you can have a lot of widely dispersed people hack
 away on a complicated piece of code and avoid total anarchy has never
 managed a software project.' - Andy Tanenbaum in 1992 on comp.os.minix

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