ucm: add LibraryConfig support

This commit allows to define private alsa-lib's configuration. When
the configuration is present, the device values ("PlaybackCTL",
"CaptureCTL", "PlaybackMixer", "CaptureMixer", "CapturePCM")
are prefixed with '_ucmHEXA.' string where HEXA is replaced by the
unique hexadecimal number identifying the opened ucm manager handle.

    Syntax 4

    LibraryConfig.a_label.SubstiConfig {
            # substituted library configuration like:
            usr_share_dir "${ConfLibDir}"
    }

    LibraryConfig.b_label.Config {
            # non-substituted library configuration like:
            usr_share_dir "/usr/share/alsa"
    }

    The File counterparts:

    LibraryConfig.c_label.SubstiFile "/some/path"
    LibraryConfig.d_label.File "/some/path"

Note that for files the contents is substituted on the request,
but the file name is always substituted (useful for ${ConfDir} etc.).

The private configuration is not saved or preserved. It's life time
belongs to the opened ucm manager handle.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2021-04-12 18:09:21 +02:00
parent 3e0140088c
commit 8f5779eb3f
11 changed files with 400 additions and 36 deletions

View file

@ -1520,9 +1520,15 @@ int snd_ctl_open(snd_ctl_t **ctlp, const char *name, int mode)
int err;
assert(ctlp && name);
err = snd_config_update_ref(&top);
if (err < 0)
return err;
if (_snd_is_ucm_device(name)) {
name = uc_mgr_alibcfg_by_device(&top, name);
if (name == NULL)
return -ENODEV;
} else {
err = snd_config_update_ref(&top);
if (err < 0)
return err;
}
err = snd_ctl_open_noupdate(ctlp, top, name, mode, 0);
snd_config_unref(top);
return err;