[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:              07-23-2006 15:04 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.



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

----------------------------------------------------------------------
 Raymond - 07-23-06 13:49 
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Please update alsa-utils to the same version of alsa-lib

speaker-test -c 2 -t wav

speaker-test -c 4 -Dsurround40 -t wav

speaker-test -c 6 -Dsurround51 -t wav

----------------------------------------------------------------------
 bitmage2 - 07-23-06 15:04 
----------------------------------------------------------------------
The installed RPM package  "alsa" is 1.0.9-23.2 (includes alsa-lib ,
alsa-utils , alsa-conf and libasound. This means alsa-lib and alsa-utils
should be the same version.

If it helps, I can install alsa 1.0.12rc1 now on a clean Linux
installtion. Should I do so?

About the test cases:

speaker-test -c 2 -t wav    # Does not produce high load
speaker-test -c 4 -Dsurround40 -t wav # Produces high load
speaker-test -c 6 -Dsurround51 -t wav # Produces high load

While playing around I made an interesting observation: The two
probleamtic cases do not produce high load, if the machine is otherwise
*completely* idle (means: don't move the mouse). If I start some activity
(for example starting Firefox, use a file manager or execute something
like "cat /boot/vmlinuz"), speaker-test immediately goes to 100% CPU time.
In this case often a "Broken pipe" can be observed (see below).
"speaker-test -c 2 -t wav" always works, no matter how hard I stress the
machine.

chris@bjork:~> speaker-test -c 6 -Dsurround51 -t wav

speaker-test 0.0.8

Playback device is surround51
Stream parameters are 48000Hz, S16_LE, 6 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 16 to 16384
Period size range from 8 to 512
Periods = 4
Buffer time size 2525
To choose buffer_size = 16384
To choose period_size = 4096
was set period_size = 512
was set buffer_size = 16384
 0 - Front Left
 4 - Center
 1 - Front Right
 3 - Rear Right
Write error: -32,Broken pipe
 2 - Rear Left
 5 - LFE

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



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