Re: [alsa-devel] Is the mixer interface in the kernel protect against concurrent access?

17 Dec 2007


      On Mon, 17 Dec 2007, Hans-Christian Egtvedt wrote:
...
Hi,
I am solving a locking bug in the at73c213 SPI sound driver, and
wondered if the mixer API is protected against concurrent access in
ALSA? Or should I implement a mutex to protect my hardware against
concurrent access?
Control r/w callbacks are protected with a semaphore - 
card->controls_rwsem . See sound/core/control.c for more details. Anyway, 
you need to protect your registers with spinlocks (if required of 
course).
Jaroslav
-----
Jaroslav Kysela perex@perex.cz
Linux Kernel Sound Maintainer
ALSA Project