Re: [PATCH] thinkpad-acpi: fix return value of volume callbacks

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Henrique de Moraes Holschuh wrote:
> On Mon, 22 Feb 2010, Clemens Ladisch wrote:
> > Fix up the volume status setting functions to return a non-zero value if
> > the control value has changed, so that the ALSA framework can correctly
> > generate control change notifications.
> 
> Please explain...

ALSA sends notifications to all mixer application when the value of
any mixer control has changed.  To be able to avoid sending them for
controls that did not actually change, it uses the return value of the
.put callback: 0 means the control value did not change; 1 means it has
changed (or might have changed), and a notification is to be sent.
<http://www.alsa-project.org/~tiwai/writing-an-alsa-driver/ch06s05.html#control-interface-callbacks-put>


Regards,
Clemens

------------------------------------------------------------------------------
Download Intel&#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
_______________________________________________
ibm-acpi-devel mailing list
ibm-acpi-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/ibm-acpi-devel

[Index of Archives]     [Linux ACPI]     [Linux Kernel]     [Linux Laptop]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite Photos]     [Yosemite Advice]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]

  Powered by Linux