[ALSA - driver 0001869]: Playing surround sound produces 100% CPU load

[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=1869> 
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Reported By:                bitmage2
Assigned To:                
======================================================================
Project:                    ALSA - driver
Issue ID:                   1869
Category:                   CORE - pcm
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Distribution:               SuSE Linux 10.0
Kernel Version:             Linux 2.6.13-15.8-default #1 Tue Feb 7 11:07:24 UTC
2006 i686 athlon i386 GNU/Linux
======================================================================
Date Submitted:             02-23-2006 00:48 CET
Last Modified:              07-26-2006 02:03 CEST
======================================================================
Summary:                    Playing surround sound produces 100% CPU load
Description: 
I am using the CS46xx with a Hercules Gametheater XP 5.1 . It plays back
stereo without problems.
I wanted to use the rest of my 5.1 speaker set, so for a test I ran the
speaker-test program. Running it without parameters or with 2 or 4.0
channels works also fine. So far so good.

But when I run it with 5.0 channels or 5.1 channels the CPU load of
speaker-test goes to 100%. I'll show the output of top along with the
command lines below (for the 2.0 and 5.1 case) in the "Additional
Information" box.



======================================================================

----------------------------------------------------------------------
 bitmage2 - 07-25-06 21:53 
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I have tested and can run multiple instances of all three commands (means: 
also the "-Drear" one works) without commenting out the "lock".
It also works if I comment out the "lock" in the "CS46xx.pcm.rear.0"
section of /usr/share/alsa/cards/CS46xx.conf .

After testing further I have good news and bad news:

The good news: "speaker-test -c 6 -Dsurround51 -t wav" does not go to 100%
CPU load when removing the "lock". :-)

So far - so good. But my original stated goal was: "use the rest of my 5.1
speaker set". And this goal includes playing back 2-channel MP3 files on
all 6 speakers.

So here's the bad news: I created a .asoundrc with a channel duplicator
"pcm.ch51dup" or "pcm.duplicate" (see below. I found those on the
internet). Using any of those two, the CPU goes again to 100% (Example:
"speaker-test -Dch51dup -c 2 -t wav").

  Christian

---  ~/.asoundrc ---------------------------

pcm.ch51dup {
    type route
    slave.pcm "surround51"
    slave.channels 6
    ttable.0.0 1
    ttable.1.1 1
    ttable.0.2 1
    ttable.1.3 1
    ttable.0.4 0.5
    ttable.1.4 0.5
    ttable.0.5 0.5
    ttable.1.5 0.5
}



---  Alternative ~/.asoundrc ---------------------------

pcm.duplicate {
    type plug
    slave.pcm "surround51"
    slave.channels 6
    route_policy duplicate
}

----------------------------------------------------------------------
 Raymond - 07-26-06 02:03 
----------------------------------------------------------------------
How many instances of surround40 or surround51 can you run ? It hard to
notice 'out of sync' when using speaker-test

You may try the upmix plugin in alsa-plugins-1.0.12rc1 for up-mixing 2
channels to 6 channels.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
02-23-06 00:48 bitmage2       New Issue                                    
02-23-06 00:48 bitmage2       Distribution              => SuSE Linux 10.0 
02-23-06 00:48 bitmage2       Kernel Version            => Linux
2.6.13-15.8-default #1 Tue Feb 7 11:07:24 UTC 2006 i686 athlon i386 GNU/Linux
02-23-06 00:54 bitmage2       Note Added: 0008164                          
02-23-06 00:55 bitmage2       Issue Monitored: bitmage2                    
07-11-06 05:58 Raymond        Note Added: 0010964                          
07-14-06 20:57 bitmage2       Note Added: 0011004                          
07-14-06 20:59 bitmage2       Note Added: 0011005                          
07-14-06 21:25 rlrevell       Note Added: 0011006                          
07-14-06 22:40 bitmage2       Note Added: 0011008                          
07-14-06 22:57 rlrevell       Note Added: 0011009                          
07-15-06 01:28 bitmage2       Note Added: 0011013                          
07-15-06 01:45 rlrevell       Note Added: 0011014                          
07-15-06 05:09 Raymond        Note Added: 0011017                          
07-15-06 07:17 Raymond        Note Edited: 0011017                         
07-23-06 11:34 bitmage2       Note Added: 0011183                          
07-23-06 13:49 Raymond        Note Added: 0011185                          
07-23-06 14:14 Raymond        Note Added: 0011186                          
07-23-06 14:16 Raymond        Note Deleted: 0011186                        
07-23-06 15:04 bitmage2       Note Added: 0011189                          
07-24-06 04:19 Raymond        Note Added: 0011209                          
07-24-06 05:04 Raymond        Note Edited: 0011209                         
07-24-06 20:38 bitmage2       Note Added: 0011214                          
07-25-06 03:00 Raymond        Note Added: 0011223                          
07-25-06 03:03 Raymond        Note Edited: 0011223                         
07-25-06 03:05 Raymond        Note Edited: 0011223                         
07-25-06 10:05 Raymond        Note Edited: 0011223                         
07-25-06 10:13 Raymond        Note Edited: 0011223                         
07-25-06 21:53 bitmage2       Note Added: 0011232                          
07-26-06 02:03 Raymond        Note Added: 0011235                          
======================================================================



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