fast playback with Intel 82801BA (ICH2)

bri...@mu.org

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May 1, 2002, 8:49:23 PM5/1/02

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-current compiled today mp3s play too fast, any ideas on how to
diagnose this?

pcm0: <Intel 82801BA (ICH2)> port 0xef00-0xef3f,0xe800-0xe8ff irq 9 at device 31.5 on pci0
pcm0: measured ac97 link rate at 44061 Hz

--
-Alfred Perlstein [alf...@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
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hod...@icir.org

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May 1, 2002, 9:09:06 PM5/1/02

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You can set a sysctl to set the ac97 link rate. I don't recall offhand what
it is (hw.snd.pcm0.ac97rate?) - "sysctl -a | grep ac97" will find it.

There is a calibration test in the ich code since various mfrs do funny things
with the clock. I'd be interested to know what boot -v output is and what
ac97 link rate works. This is the second box reported failing on this
recently.

- Orion

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bri...@mu.org

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May 2, 2002, 6:06:16 PM5/2/02

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* Orion Hodson <hod...@icir.org> [020501 18:10] wrote:
> /-- Alfred Perlstein wrote:
> | -current compiled today mp3s play too fast, any ideas on how to
> | diagnose this?
> |
> | pcm0: <Intel 82801BA (ICH2)> port 0xef00-0xef3f,0xe800-0xe8ff irq 9 at device
> | 31.5 on pci0
> | pcm0: measured ac97 link rate at 44061 Hz
>
> You can set a sysctl to set the ac97 link rate. I don't recall offhand what
> it is (hw.snd.pcm0.ac97rate?) - "sysctl -a | grep ac97" will find it.
>
> There is a calibration test in the ich code since various mfrs do funny things
> with the clock. I'd be interested to know what boot -v output is and what
> ac97 link rate works. This is the second box reported failing on this
> recently.

/usr/src/sys/sys % sysctl -a | grep ac97
ac97 2 1K 1K 2 16,256
hw.snd.pcm0.ac97rate: 44061

I can get you boot -v later.

--
-Alfred Perlstein [alf...@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
Tax deductible donations for FreeBSD: http://www.freebsdfoundation.org/

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bri...@mu.org

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May 3, 2002, 2:01:27 PM5/3/02

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* Orion Hodson <hod...@icir.org> [020501 18:10] wrote:

> /-- Alfred Perlstein wrote:
> | -current compiled today mp3s play too fast, any ideas on how to
> | diagnose this?
> |
> | pcm0: <Intel 82801BA (ICH2)> port 0xef00-0xef3f,0xe800-0xe8ff irq 9 at device
> | 31.5 on pci0
> | pcm0: measured ac97 link rate at 44061 Hz
>
> You can set a sysctl to set the ac97 link rate. I don't recall offhand what
> it is (hw.snd.pcm0.ac97rate?) - "sysctl -a | grep ac97" will find it.
>
> There is a calibration test in the ich code since various mfrs do funny things
> with the clock. I'd be interested to know what boot -v output is and what
> ac97 link rate works. This is the second box reported failing on this
> recently.

This makes it sound almost perfect:

sysctl hw.snd.pcm0.ac97rate=55000

the default 44061 is bad.

--
-Alfred Perlstein [alf...@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
Tax deductible donations for FreeBSD: http://www.freebsdfoundation.org/

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tlam...@mindspring.com

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May 3, 2002, 2:11:25 PM5/3/02

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Alfred Perlstein wrote:
> This makes it sound almost perfect:
>
> sysctl hw.snd.pcm0.ac97rate=55000
>
> the default 44061 is bad.

I thought this was because it's the CD sample rate...

-- Terry

jh...@icomtek.csir.co.za

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May 3, 2002, 3:09:51 PM5/3/02

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> This makes it sound almost perfect:
>
> sysctl hw.snd.pcm0.ac97rate=55000
>
> the default 44061 is bad.

What about 56000? Our Dells seem to use it. I'm not sure what is so magic
about it. Maybe they wanted to cater for modems on the ac97 channel.

John
--
John Hay -- John...@icomtek.csir.co.za / jh...@FreeBSD.org

bri...@mu.org

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May 3, 2002, 3:11:54 PM5/3/02

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* John Hay <jh...@icomtek.csir.co.za> [020503 12:09] wrote:
> > > | -current compiled today mp3s play too fast, any ideas on how to
> > > | diagnose this?
> > > |
> > > | pcm0: <Intel 82801BA (ICH2)> port 0xef00-0xef3f,0xe800-0xe8ff irq 9 at device
> > > | 31.5 on pci0
> > > | pcm0: measured ac97 link rate at 44061 Hz
> >
> > This makes it sound almost perfect:
> >
> > sysctl hw.snd.pcm0.ac97rate=55000
> >
> > the default 44061 is bad.
>
> What about 56000? Our Dells seem to use it. I'm not sure what is so magic
> about it. Maybe they wanted to cater for modems on the ac97 channel.

That sounds fine also, basically if i go lower then it sounds sped
up, higher and it sounds slow.

-Alfred