[ALSA - driver 0001440]: headphone output loops to microphone input

[bugtrack@alsa-project.org]

A NOTE has been added to this issue.
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<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1440> 
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Reported By:                dyfrgi
Assigned To:                
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Project:                    ALSA - driver
Issue ID:                   1440
Category:                   PCI - intel8x0
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     new
Distribution:               Gentoo
Kernel Version:             2.6.13.1
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Date Submitted:             09-22-2005 00:13 CEST
Last Modified:              12-31-2005 07:47 CET
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Summary:                    headphone output loops to microphone input
Description: 
I cannot use the headphone port when using full duplex on my laptop. Here
are four scenarios, and the results:

1. System speakers, no microphone plugged in
RESULTS:
When recording from the microphone input, there is no sound. As expected.

2. System speakers, microphone plugged in
RESULTS:
Only the sound that should be picked up by the microphone is recorded
through the microphone input. As expected.

3. Headphones plugged in, microphone not plugged in.
RESULTS:
No sound when recording. As expected.

4. Headphones plugged in, microphone plugged in.
RESULTS:
Audio coming in through the microphone input is a combination of the
expected audio and the audio that is being played through the headphone
output. This is the problem.

Could this be an ALSA issue, or should I have the laptop hardware looked
at? I should note that this also happens if I use the OSS driver. That
doesn't mean it's not a driver issue, though; it could be that some
register is not being set up properly.

The loopbacked volume is lower than if I set Mix or Mix Mono to be the
capture channel. I'm using jaaa with noise output turned on to monitor.
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----------------------------------------------------------------------
 rlrevell - 12-31-05 03:20 
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Any improvement with later ALSA releases?

----------------------------------------------------------------------
 dyfrgi - 12-31-05 07:47 
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Ah. Yes. Turns out to have been an issue with my microphone - it's just
hideously leaky, I suppose. If I use a different mic, there's no problem.
Sorry for not checking back after I determined this.

On the plus side, the bug can now be closed.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
09-22-05 00:13 dyfrgi         New Issue                                    
09-22-05 00:13 dyfrgi         Distribution              => Gentoo          
09-22-05 00:13 dyfrgi         Kernel Version            => 2.6.13.1        
12-31-05 03:20 rlrevell       Note Added: 0007324                          
12-31-05 07:47 dyfrgi         Note Added: 0007352                          
======================================================================




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