Thanks for your help! Haven't nailed it down yet. I'm not sure what I should look for in the dmesg output. It's a bit lengthy to post the whole thing here. It does refer to some pnp addresses:
pnp: 00:05: ioport range 0x250-0x257 has been reserved <-- this is the address range Windows used for the sound card.
pnp: 00:05: ioport range 0x270-0x271 has been reserved
pnp: 00:05: ioport range 0x40b-0x40b has been reserved
pnp: 00:05: ioport range 0x4d6-0x4d6 has been reserved
pnp: 00:05: ioport range 0xc48-0xc4a has been reserved
pnp: 00:05: ioport range 0xc6c-0xc6d has been reserved
pnp: 00:0f: ioport range 0x4d0-0x4d1 has been reserved
pnp: 00:0f: ioport range 0x800-0x87f has been reserved
pnp: 00:0f: ioport range 0xc10-0xc1f has been reserved
pnp: 00:0f: ioport range 0xc80-0xc9f could not be reserved
And here is the output of modinfo:
root@bandit:/ # modinfo snd-es18xx
filename: /lib/modules/2.6.10-5-386/kernel/sound/isa/snd-es18xx.ko
author: Christian Fischbach <fishbach@pool.informatik.rwth-aachen.de>, A bramo Bagnara <abramo@alsa-project.org>
description: ESS ES18xx AudioDrive
license: GPL
parm: index:Index value for ES18xx soundcard.
parm: id:ID string for ES18xx soundcard.
parm: enable:Enable ES18xx soundcard.
parm: isapnp:PnP detection for specified soundcard.
parm: port:Port # for ES18xx driver.
parm: mpu_port:MPU-401 port # for ES18xx driver.
parm: fm_port:FM port # for ES18xx driver.
parm: irq:IRQ # for ES18xx driver.
parm: dma1
MA 1 # for ES18xx driver.
parm: dma2
MA 2 # for ES18xx driver.
vermagic: 2.6.10-5-386 preempt 386 gcc-3.3
depends: snd-pcm,snd,snd-opl3-lib,snd-mpu401-uart
alias: pnp:cESS1868dESS1868dESS0000*
alias: pnp:cESS1868dESS8601dESS8600*
alias: pnp:cESS1868dESS8611dESS8610*
alias: pnp:cESS0003dESS1869dESS0006*
alias: pnp:cESS1869dESS1869dESS0006*
alias: pnp:cESS1878dESS1878dESS0004*
alias: pnp:cESS1879dESS1879dESS0009*
srcversion: 2A7952BB92B73FC3A09BEC9