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by Daniel T Chen
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alsa-utils README.Debian |
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Contents
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--------
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News
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Restoring mixer levels |
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Storing mixer levels |
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Error messages |
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News
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----
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by Luke Yelavich
Merge with Debian |
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Last updated 12 April 2009 |
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by Daniel T Chen
Initial Hardy changes |
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Restoring mixer levels |
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ALSA drivers initialize hardware mixer levels to zero. It is usually |
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desirable to set things up so that the mixer levels for basic sound |
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output are automatically raised to reasonable levels after the drivers |
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have completed their initialization. |
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Currently, alsa-utils accomplishes this by having its initscript's |
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"start" method restore mixer levels to what they were the last time |
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they were saved (see below). The levels are stored in the file |
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/var/lib/alsa/asound.state. If either the latter file or the alsactl |
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program is not available then amixer is used to set mixer levels to |
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"reasonable" default values. |
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To set mixer levels to "reasonable" default values from the command |
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line (i.e., without trying first to restore saved values), run |
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by Luke Yelavich
* Merge from debian unstable, remaining changes: |
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"/sbin/alsa-utils reset". |
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by Daniel T Chen
Initial Hardy changes |
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For modular drivers on a udev system, the /lib/alsa/udev script runs |
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the initscript "start" method after a driver has initialized and its |
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associated control device has been created. |
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For integral drivers and modular ones loaded very early in the boot |
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process, the initscript is configured to be run as part of runlevel |
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initialization. Restoration of mixer levels on bootup can be disabled |
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by configuring the alsa-utils "service" as stopped in runlevel S. On a |
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system that uses sysv-rc this means that you should RENAME |
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/etc/rcS.d/S50alsa-utils to /etc/rcS.d/K50alsa-utils. The symlink |
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should not be deleted---only renamed. |
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Storing mixer levels |
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By default mixer levels are stored before shutdown by the initscript's |
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"stop" method. The initscript is run with "stop" in runleves 0 and 6. |
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To disable this behavior, if you are using sysv-rc, REMOVE the |
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"K50alsa-utils" symbolic links from /etc/rc0.d/ and /etc/rc6.d/. |
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The symlinks should be removed, not just renamed. |
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Note that this scheme is different from and simpler than the scheme |
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that was used by the "alsa" initscript when it contained the code |
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that implemented mixer level storing and restoring. The runlevels_save |
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environment variable is no longer used---indeed, there is no |
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/etc/default/ file for alsa-utils at all---and there is no longer a |
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choice of values for "alsactl_store_on_shutdown". Now "alsactl store" |
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is run on shutdown unconditionally; however, this can be disabled by |
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configuring the alsa-utils "service" as floating in runlevels 0 and 6, |
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as described above. |
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Error messages |
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If the initscript "start" method is run early in the boot process, |
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before /usr/ is mounted, then it may print an error message. The |
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message can be ignored because the initscript gets run again later in |
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the boot process. |
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by Luke Yelavich
* Merge from debian unstable, remaining changes: |
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/sbin/alsa-utils: Warning: No alsactl program available. |
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1
by Daniel T Chen
Initial Hardy changes |
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If you use the snd-cs46xx module then you may see messages like this: |
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Jan 26 14:32:50 foo kernel: ALSA ../../alsa-kernel/pci/cs46xx/cs46xx_lib.c:427: cs46xx: failure waiting for FIFO command to complete |
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This arises from a bug in the driver, but so far I have yet to |
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observe any consequent malfunction in the sound card. |