Try compiling out the Dummy driver and Virtual MIDI Card driver. I believe ALSA assigns 
/dev/sound/xx[1->x] as a direct result of the order of detection (and listing). This was at least 
my experience. Removing the other drivers should move it back to slot #0 (/dev/sound/xx), 
might fix it. 

It doesn't work, sigh...

Kernel is 2.5.67,

Advanced Linux Sound Architecture Driver Version 0.9.2 (Thu Mar 20 13:31:57 
2003 UTC).
request_module: failed /sbin/modprobe -- snd-card-0. error = -16
no UART detected at 0xffff
Motu MidiTimePiece on parallel port irq: 7 ioport: 0x378
ALSA sound/drivers/mpu401/mpu401.c:76: specify port
PCI: Found IRQ 5 for device 00:0d.0
ALSA device list:
  #0: Dummy 1
  #1: 
  #2: ESS Maestro3 PCI at 0x1800, irq 5

Following my .config# Sound
#
CONFIG_SOUND=y

#
# Advanced Linux Sound Architecture
#
CONFIG_SND=y
CONFIG_SND_SEQUENCER=y
# CONFIG_SND_SEQ_DUMMY is not set
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
CONFIG_SND_SEQUENCER_OSS=y
CONFIG_SND_VERBOSE_PRINTK=y
CONFIG_SND_DEBUG=y
CONFIG_SND_DEBUG_MEMORY=y
CONFIG_SND_DEBUG_DETECT=y

#
# Generic devices
#
CONFIG_SND_DUMMY=y
# CONFIG_SND_VIRMIDI is not set
CONFIG_SND_MTPAV=y
CONFIG_SND_SERIAL_U16550=y
CONFIG_SND_MPU401=y

#
# ISA devices
#
all are not set
#
# PCI devices
#
# CONFIG_SND_ALI5451 is not set
# CONFIG_SND_CS46XX is not set
# CONFIG_SND_CS4281 is not set
# CONFIG_SND_EMU10K1 is not set
# CONFIG_SND_KORG1212 is not set
# CONFIG_SND_NM256 is not set
# CONFIG_SND_RME32 is not set
# CONFIG_SND_RME96 is not set
# CONFIG_SND_RME9652 is not set
# CONFIG_SND_HDSP is not set
# CONFIG_SND_TRIDENT is not set
# CONFIG_SND_YMFPCI is not set
# CONFIG_SND_ALS4000 is not set
# CONFIG_SND_CMIPCI is not set
# CONFIG_SND_ENS1370 is not set
# CONFIG_SND_ENS1371 is not set
CONFIG_SND_ES1938=y
CONFIG_SND_ES1968=y
CONFIG_SND_MAESTRO3=y
# CONFIG_SND_FM801 is not set
# CONFIG_SND_ICE1712 is not set
# CONFIG_SND_ICE1724 is not set
# CONFIG_SND_INTEL8X0 is not set
# CONFIG_SND_SONICVIBES is not set
# CONFIG_SND_VIA82XX is not set

#
# Open Sound System
#
# CONFIG_SOUND_PRIME is not set

# 
# Generic devices 
# 
CONFIG_SND_DUMMY=y 
# CONFIG_SND_VIRMIDI is not set 
CONFIG_SND_MTPAV=y 
CONFIG_SND_SERIAL_U16550=y 
CONFIG_SND_MPU401=y 
 
Disable all of those, retry. That dummy device is still occupying slots. Does the ess even have 
an MPU401 interface? 

Hi,
I think I undestood wich is the option that cause the error I reported,
[ ]     OSS Sequencer API
If I enable that option I get the following error
Copiare errore

Now my dmesg is:
Advanced Linux Sound Architecture Driver Version 0.9.2 (Thu Mar 20 13:31:57 
2003 UTC).
PCI: Found IRQ 5 for device 00:0d.0
ALSA device list:
  #0: Dummy 1
  #1: Virtual MIDI Card 1
  #2: ESS Maestro3 PCI at 0x1800, irq 5
  
But I still not able to play _any_ sound, I don't think that it is a problem
with my init scripts because with 2.4 I have _no_ problem.

Any hint ?

Any way, here it is my .config (and Alistar, thank you so much for your hint)

# Sound
#
CONFIG_SOUND=y

#
# Advanced Linux Sound Architecture
#
CONFIG_SND=y
CONFIG_SND_SEQUENCER=y
CONFIG_SND_SEQ_DUMMY=y
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
# CONFIG_SND_SEQUENCER_OSS is not set
CONFIG_SND_VERBOSE_PRINTK=y
CONFIG_SND_DEBUG=y
CONFIG_SND_DEBUG_MEMORY=y
CONFIG_SND_DEBUG_DETECT=y

#
# Generic devices
#
CONFIG_SND_DUMMY=y
CONFIG_SND_VIRMIDI=y
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_SERIAL_U16550 is not set
# CONFIG_SND_MPU401 is not set

#
# ISA devices
# All are not set

#
# PCI devices
#
# CONFIG_SND_ALI5451 is not set
# CONFIG_SND_CS46XX is not set
[all not set]
CONFIG_SND_MAESTRO3=y
# CONFIG_SND_FM801 is not set
[all not set]


# Open Sound System
#
# CONFIG_SOUND_PRIME is not set

Please read my comments. 
 
I don't know how to make this any clearer to you. 
 
If the dummy and Virtual Midi card driver are in slots 0 and 1, they might be receiving the audio 
before applications choose 2. WHEN you try what I've suggested and disable all devices except 
your soundcard, you MIGHT see it move to slot 0, and stuff might start to work again. 

Ok, I am stupid, really...
I was under the impression that in the past I tried what you suggested me 
with no results. But I was totaly wrong.
I think I confused the following options:
CONFIG_SND_SEQ_DUMMY
and
CONFIG_SND_DUMMY

What you suggested me is _100%_ correct. Sorry for the noise...


#
# Advanced Linux Sound Architecture
#
CONFIG_SND=y
CONFIG_SND_SEQUENCER=y
CONFIG_SND_SEQ_DUMMY=y
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
# CONFIG_SND_SEQUENCER_OSS is not set
CONFIG_SND_VERBOSE_PRINTK=y
CONFIG_SND_DEBUG=y
CONFIG_SND_DEBUG_MEMORY=y
CONFIG_SND_DEBUG_DETECT=y

#
# Generic devices
#
# CONFIG_SND_DUMMY is not set
# CONFIG_SND_VIRMIDI is not set
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_SERIAL_U16550 is not set
# CONFIG_SND_MPU401 is not set

While dmesg says:
Advanced Linux Sound Architecture Driver Version 0.9.2 (Thu Mar 20 13:31:57 
2003 UTC).
PCI: Found IRQ 5 for device 00:0d.0
ALSA device list:
  #0: ESS Maestro3 PCI at 0x1800, irq 5
  
And now I am able to play sound. ;)

Again, thank you so much.

I think I can close the bug...