AC3 Passthru on SB Live

AC3 Passthru on SB Live

[James Courtier-Dutton]

Hello

AC3 passthru on the SB Live does not seem to work on all platforms with the
latest alsa-cvs. (26-2-2002)
It works on my system, which is a SB Live Rev 6, which only started working
recently.
It does not work on a SB Live rev 7 (I don't have this, but others have
reported.)

Can anyone comment on which SB Live revisions work, and which do not.

All the SB Live versions seem to work with the emu10k1 kernel drivers.

Cheers
James


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RE: AC3 Passthru on SB Live

[James Courtier-Dutton]

As a small extra, the emu10k1 kernel driver which support oss, has a few
bits of info which might be of help
>From the emu10k1 linux kernel developers: -
We allocate memory with pci_alloc_consistent() which according to
DMA-mapping.txt assures 32-bits PCI addresses. On top of that
we set a dma_mask (with pci_set_dma_mask) of 29 bits (512Mib).

Also: -
29 bit (512MiB), mostly speculation/trial-and-error though. See main.c and
the pci_set_dma_mask() calls.

Does this help alsa09 at all ?

Cheers
James


> -----Original Message-----
> From: James Courtier-Dutton [mailto:James@superbug.demon.co.uk]
> Sent: 27 February 2002 15:51
> To: alsa-devel@lists.sourceforge.net
> Subject: AC3 Passthru on SB Live
>
>
> Hello
>
> AC3 passthru on the SB Live does not seem to work on all
> platforms with the latest alsa-cvs. (26-2-2002)
> It works on my system, which is a SB Live Rev 6, which only
> started working recently.
> It does not work on a SB Live rev 7 (I don't have this, but
> others have reported.)
>
> Can anyone comment on which SB Live revisions work, and which do not.
>
> All the SB Live versions seem to work with the emu10k1 kernel drivers.
>
> Cheers
> James
>


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Re: AC3 Passthru on SB Live

[Takashi Iwai]

At Wed, 27 Feb 2002 15:50:47 -0000,
James Courtier-Dutton wrote:
> 
> Hello
> 
> AC3 passthru on the SB Live does not seem to work on all platforms with the
> latest alsa-cvs. (26-2-2002)
> It works on my system, which is a SB Live Rev 6, which only started working
> recently.

Just curious - are you using a kernel with HIGHMEM config?
If working with this config, then it should not be a problem of memory
allocation.
Or, it might be the problem of dma mask.  ALSA uses 31bit mask while
Creative's driver uses 29bit.  But anyway this won't affect unless you
have more than 512MB RAM and kernel ocasionally allocates the area
greater than 512MB.


> It does not work on a SB Live rev 7 (I don't have this, but others have
> reported.)

IIRC, we still don't implement the direct pass-through method (PASS2
in Creative's driver) for the recent models (rev.7 or newer).
Perhaps this makes difference.


Takashi

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RE: AC3 Passthru on SB Live

[James Courtier-Dutton]

> Or, it might be the problem of dma mask.  ALSA uses 31bit mask while
> Creative's driver uses 29bit.  But anyway this won't affect unless you
> have more than 512MB RAM and kernel ocasionally allocates the area
> greater than 512MB.
Creative's driver uses 29bit mask, because a 32bit mask was creating
problems with some users.
Maybe the SB Live is only capable of 29bits for DMA.

Cheers
James


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Re: AC3 Passthru on SB Live

[Takashi Iwai]

At Wed, 27 Feb 2002 17:19:44 -0000,
James Courtier-Dutton wrote:
> 
> > Or, it might be the problem of dma mask.  ALSA uses 31bit mask while
> > Creative's driver uses 29bit.  But anyway this won't affect unless you
> > have more than 512MB RAM and kernel ocasionally allocates the area
> > greater than 512MB.
> Creative's driver uses 29bit mask, because a 32bit mask was creating
> problems with some users.
> 
> Maybe the SB Live is only capable of 29bits for DMA.

well, as stated above, alsa uses 31bit (not 32), so this is not
problem usually, because kernel's pci memory allocator checks only
whether the mask is 32bit or not, and if it's not 32bit, the allocator
uses always GFP_DMA flag.


Takashi

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Re: AC3 Passthru on SB Live

[Markus Plail]

Date: 28 Feb 2002 12:01:45 +0100
Message-ID: <878z9dswdi.fsf@www.gitteundmarkus.de>
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* "Takashi" == Takashi Iwai schrieb am Wed, 27 Feb 2002 17:47:39 +0100:
> At Wed, 27 Feb 2002 15:50:47 -0000,
> James Courtier-Dutton wrote:
>> Hello
>> 
>> AC3 passthru on the SB Live does not seem to work on all platforms
>> with the latest alsa-cvs. (26-2-2002) It works on my system, which
>> is a SB Live Rev 6, which only started working recently.

> Just curious - are you using a kernel with HIGHMEM config?  If
> working with this config, then it should not be a problem of memory
> allocation.  Or, it might be the problem of dma mask.  ALSA uses
> 31bit mask while Creative's driver uses 29bit.  But anyway this
> won't affect unless you have more than 512MB RAM and kernel
> ocasionally allocates the area greater than 512MB.
James has a rev 06 card so it doesn't apply to him. I have a rev07
card and it doesn't work and I don't have HIGHMEM enabled.

>> It does not work on a SB Live rev 7 (I don't have this, but others
>> have reported.)

> IIRC, we still don't implement the direct pass-through method (PASS2
> in Creative's driver) for the recent models (rev.7 or newer).
> Perhaps this makes difference.
Are there plans to implement this? Can I help with doing that? Don't 
know if any of the developers have a rev07 card.

Regards
Markus


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