sound slowdown when accessing ide cdrom

[Christian Ohm]

hi.

i'm using an old ide cdrom drive and a soundblaster awe64 isa pnp sound card
(using the alsa-driver). when i'm accessing the cdrom, the sound playback
slows down. a little and irregularly when copying files, more and almost
constant (about 10%) when grabbing audio using cdparanoia. it works perfect
when using the scsi cdrom drive.

i'm using an nmc 8tax+ (via kt133) mainboard with duron700 and 512mb ram,
one isa slot with the soundblaster awe64 pnp, a dawicontrol dc2975u scsi
controller (symbios logic 53c875), a matrox g400, a sis900 ethernet
controller. the ide cdrom drive is an old 4x speed drive
(/proc/ide/ide1/hdc/model says 'MATSHITA CR-581') connected to the second
ide port (without slave). i'm using kernel 2.4.9 and the oss emulation of
alsa (debian unstable packages 0.9+0beta7-1). i also tested this with the
low latency patch (which didn't change anything).

anyone knows what happens there? it seems like there's some strange
interaction of the ide cdrom driver and a timer used by (at least) alsa.

if there's some info missing i'd be happy to provide it.

bye
christian ohm

ps: since i'm not subscribed to this list, please cc all replies to me
([e-mail]). thanks.