Re: Just a quick question...Damn - last msg w/ continue

[Takashi Iwai <tiwai@suse.de>]

At Wed, 14 Aug 2002 21:13:36 -0700,
Jim wrote:
> 
> > > Unfortunately the i810 driver is one of the undisclosed code family. I
> > > haven't used the nforce so I don't know about it.
> 
> I went out looking for information - being from Intel - SURELY it's
> documented, and such information is publicly available.... I've found a
> plethora of information - but everything about the design of the ac97 spec
> indicates one register set, one set of dmas ... one could interpret one
> portion... there's 256 ranges of base registers one can select - but then
> you'd have a full set of mixing registers etc - just totally impracticle :/
> and therefore 256*3 dma units ... which isn't all that much memory andwidth
> at 256*44.1khz*16*2 is only 45MB/sec ...  less than a hard disk... and I
> don't understand the PCI interface entirely.... but then I did go back to
> nVidia's page on the nForce chip
>    http://www.nvidia.com/docs/lo/557/SUPP/nForce_MCP_Overview.pdf
> and amidst all of that it says - DirectX blahblah 256 channels audio blah 64
> 3d ... and I think however that these are accomplished in software, and that
> the hardware spec has nothing to do with this... and this minor 'marketing
> hype' has been trimmed to be
>   'motherboard - audio- ac97 with 256 channels.'
>   though appropritely marketed as
>   ' motherboard - audio - Direct Sound AC97 Audio'
> 
> went out for a general search at the conclusion of my wanderings and find
> that the maestro indeed has 64 register sets - which when a audio interrupt
> is received would greatly increase the time to figure out uhh which
> (virtual) card has the completion event...
> 
> excerpt from maestro.c changelog
>  Then we have beasts
> 90      *	like the APU interface that is indirect registers gotten at
> through
> 91      *	the main maestro indirection.  Ouch.  We spinlock around the
> actual
> 92      *	ports on a per card basis.  This means spinlock activity at each
> IO
> 93      *	operation, but the only IO operation clusters are
> 
> 
> Okay - so I'm over it.  now - wonder if I should use JACK or ESD?

yes, unless your cards support it :)
(or alternatively artsd, too.)

the drivers with hardware mixing are:
	emu10k1, trident, ali5451, ymfpci, es1968, maestro3, cs46xx, gus*


Takashi


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