Most of open functions in alsa-lib have the call pattern:
snd_config_update();
return snd_xxx_open(x, snd_config, ...);
This means that the toplevel config gets updated, and passed to a
local open function. Although snd_config_update() itself has a
pthread mutex to be thread safe, the whole procedure above isn't
thread safe. Namely, the global snd_config tree may be deleted and
recreated at any time while the open function is being processed.
This may lead to a data corruption and crash of the program.
For avoiding the corruption, this patch introduces a refcount to
config tree object. A few new helper functions are introduced as
well:
- snd_config_update_ref() does update and take the refcount of the
toplevel tree. The obtained config tree has to be freed via
snd_config_unref() below.
- snd_config_ref() and snd_config_unref() manage the refcount of the
config object. The latter eventually deletes the object when all
references are gone.
Along with these additions, the caller of snd_config_update() and
snd_config global tree in alsa-lib are replaced with the new helpers.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Otherwise, they get misinterpreted as argument separators
in USB-Audio PCM definitions, and thus prevent SPDIF blacklist entries
from working.
While at it, add my Logitec C910 webcam to the SPDIF blacklist.
Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Fixed problem with EOF detection in freestring parser.
Fixed problem with run-time argument parsing (snd_config_load()->snd_config_load_override() replace).
Added more documentation for configuration run-time arguments and hooks.
Fixed the behaviour of snd_config_search_definition() - implicit and explicit base.
- changed snd_config_get_id function to follow semantic of other get functions
- added snd_config_test_id
- added runtime pointer type (not persistent)
- added snd_config_make_pointer, snd_config_set_pointer, snd_config_get_pointer
- added type/contents checking for callback functions
- changed 'void *private_data' to 'snd_config_t *private_data'
- renamed card_strtype functions to card_driver
Control:
- fixed passing parameters to snd_ctl_async
Async handlers:
- added public snd_async_handler_get_signo function
Documentation:
- moved all documentation to source files
Added back modified snd_config_refer_load function.
Added snd_func_private_pcm_subdevice function.
Removed the callback from the snd_sctl_build function (no more required).
Modified alsa.conf to use refer {} blocks again.
Modified card specific conf files to use new snd_func_private_pcm_subdevice function.
- added pcm.front, pcm.rear, pcm.center_lfe blocks
* Added configuration for EMU10K1 (it's fully working one!!!)
* snd_config_redirect_load->snd_config_refer_load rename
* snd_config_search_alias code change (works also with pairs base.key)
* cleanups in the evaluate function (the function prototype has been changed)
The snd_config_expand functions expands the runtime contents (@func...).
Removed the environment variable replace code from the configuration parser.
Updated the alsa.conf configuration file.
The configuration root (snd_config) can be specified for the internal routines.
The pcm_hooks code was recoded (independent code moved to control/setup.c).
Improved the pcm_multi plugin (added master configuration).
Improved the variable substitution (all references in a string are replaced).
Added special redirect loading code (to separate card dependant code to
single files).
