[alsa-devel] [PATCH 1/1] Changing the Multi Track Peak control from MIXER to PCM type

Jaroslav Kysela perex at perex.cz
Tue Oct 6 15:41:41 CEST 2009

On Tue, 6 Oct 2009, Pavel Hofman wrote:

> Takashi Iwai wrote:
>> At Tue,  6 Oct 2009 14:51:06 +0200,
>> pavel.hofman at ivitera.com wrote:
>>> From: Pavel Hofman <pavel.hofman at ivitera.com>
>>> * The "Multi Track Peak" control is now of PCM type, to avoid
>>>   confusing users in other alsa mixers.
>> We still need to handle the older kernels, so it has to retry with
>> IFACE_MIXER as fallback.
>> Could you fix and repost?
> Sure, just would you please tell me which snd_ctl_elem method to use to
> check for existence of the control? I have no experience with alsa-lib

Just use snd_ctl_elem_read() as in update_peak_switch(). If an error is 
returned, control is not present.


Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.

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