.\" $NetBSD: eap.4,v 1.17.74.1 2024/06/17 18:02:28 martin Exp $
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.\" by Lennart Augustsson.
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.Dd May 16, 2024
.Dt EAP 4
.Os
.Sh NAME
.Nm eap
.Nd AudioPCI audio device driver
.Sh SYNOPSIS
.Cd "eap*    at pci? dev ? function ?"
.Cd "options EAP_USE_BOTH_DACS"
.Pp
.Cd "audio*  at audiobus?"
.Cd "joy*    at eap?"
.Cd "midi*   at eap?"
.Sh DESCRIPTION
The
.Nm
driver provides support for the Ensoniq AudioPCI and Creative Labs
SoundBlaster PCI series of audio cards.
All models based on the ES1370, ES1371, and ES1373 chips are supported.
.Pp
By specifying:
.Pp
.D1 Cd options EAP_USE_BOTH_DACS
.Pp
a second audio device is attached.
This can be used for audio output simultaneously with the primary DAC.
You can use it simply by directing audio output to the additional
.Pa /dev/audioX
device associated with it.
.Sh SEE ALSO
.Xr ac97 4 ,
.Xr audio 4 ,
.Xr joy 4 ,
.Xr midi 4 ,
.Xr pci 4
.Sh HISTORY
The
.Nm
device driver appeared in
.Nx 1.4 .
.Sh CAVEATS
The joystick port hardware works by emulating a legacy
.Xr isa 4
joystick port, bypassing the
.Xr pci 4
bus method for address allocation.
This is unlikely to work on PCI busses other than the primary one.
There is also a possibility for conflicts with real ISA devices
because the PCI bus is probed before ISA.
Use with caution.
.Pp
The
.Dv EAP_USE_BOTH_DACS
option is rather redundant after the introduction of the in-kernel audio
mixer, and may be removed in a future release.
It is possible that it could be used to accelerate mixing streams by
taking advantage of the hardware's features, but currently the
additional (small) overhead of the kernel mixer is impossible to bypass,
since
.Nx
no longer allows userspace software to write directly to audio hardware.
The
.Nm
hardware only features one clock, so generally the second audio device
must be configured in the same way as the first.