[pulseaudio-discuss] A question on hal-detect module source code

Lennart Poettering lennart at poettering.net
Tue Mar 3 11:20:14 PST 2009

On Wed, 25.02.09 11:45, Bu, Long (long.bu at intel.com) wrote:

> Hi,
> 	I am reading its code and wondering why the filter_cb is needed to handle ACLAdded 
> 	And ACLRemoved etc signals.  Since there are
> 		libhal_ctx_set_device_added(u->context, device_added_cb);
>     		libhal_ctx_set_device_removed(u->context, device_removed_cb);
> 		libhal_ctx_set_device_new_capability(u->context, new_capability_cb);
> 	    libhal_ctx_set_device_lost_capability(u->context, lost_capability_cb);
> 	in pa__init, and the callbacks will handle for those signals.

libhal does not provide a callback that is called whenever an ACL
entry is removed/added to a device file. All it provides are callbacks
for the devices themselves being added/removed.

When the active session is switched HAL will make sure that the new
active user acn access the audio devices and the old user can no
longer. PA needs to know that so that it can suspend/resume its devices.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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