Re: [Alsa-user] CT5880 Four Channel Sound

[Patrick B. <sga...@fa...>]

> > I have a Gigabyte motherboard (GA7DXR+) with an integrated
> > Ensoniq/Creative CT5880 AudioPCI sound card. Here is the lspci output:
> > 
> > 00:0e.0 Multimedia audio controller: Ensoniq CT5880 [AudioPCI] (rev 04)
> >       Subsystem: Giga-byte Technology: Unknown device a001
> >       Flags: bus master, slow devsel, latency 32, IRQ 12
> >       I/O ports at e400 [size=64]
> >       Capabilities: [dc] Power Management version 2
> > 
> > I am currently using the ens1371 driver from the alsa-driver-0.9.6rc6
> > tarball (built from source) with Kernel 2.4.14 on Redhat 7.2
> >
> > My question is about using the line-in on the back of the sound card as
> > a second output for four channel sound. The ens1371 driver provides two
> > pcm devices, Device 0 for playback and capture and Device 1 for
> > playback. snd-pcm-oss properly maps these devices to /dev/dsp0 and
> > /dev/adsp0, and sound played through both devices comes out the line-out
> > (front channels).
> >
> > The motherboard manual indicates that the sound card is able to produce
> > four channel sound by using the line-out for the two front channels and
> > the line-in for the rear two channels. The Windows drivers for this card
> > support this. alsamixer also provides controls for the "surround"
> > channels and separate "3D" controls for the front and surround channels.
> >
> > I assume using the line-in as a second output requires driver support to
> > switch this feature on. I noticed a feature in the driver called "Line
> > in to AOUT", but this is ifdef'd to only work with a 1370 chip (I
> > believe the CT5880 is a 1373.) Would it be difficult to add this
> > feature? Is it documented by Creative?
> 
> We have no info about four channels mode for ES1373.
> 
>                                                 Jaroslav

The "Line in to AOUT" feature of 1370-based cards seems to be
implemented by setting the first general purpose register of the 1370
chip (XCTL0). This makes pin 47 of the chip high, and presumably makes
"line in" a second output. However, according to the 1373 specifications
which I found on the net, this chip has a GPIO instead of general
purpose registers. Is it possible that four-channel mode is implemented
by way of the GPIO? Perhaps I could write some values to these registers
and see if I can enable four channel mode.

Would I have to contact Creative or my motherboard manufacturer if I
wanted to know these settings? Would it be feasible to hack the Windows
drivers to find out?

Thanks for your help.

-Patrick