ucm: suppress the no device (no UCM card) errors on request

It seems that users are confused when the UCM configuration
is not ready for the particular hardware. Actually, we don't
allow a fine grained message classification in alsa-lib and
UCM API. Allow suppression of this specific type of messages
on the application request (typically alsactl).

BugLink: https://github.com/alsa-project/alsa-utils/issues/111
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/ucm/main.c b/src/ucm/main.c
index d4645e4add5ebabcea09e2d1137a2b59f6ae85d8..078cfd641fe76027d49ac55d1380259e0e9e4699 100644 (file)
--- a/src/ucm/main.c
+++ b/src/ucm/main.c
@@ -1383,6 +1383,11 @@ int snd_use_case_mgr_open(snd_use_case_mgr_t **uc_mgr,
        INIT_LIST_HEAD(&mgr->variable_list);
        pthread_mutex_init(&mgr->mutex, NULL);
 
+       if (card_name && *card_name == '-') {
+               card_name++;
+               mgr->suppress_nodev_errors = 1;
+       }
+
        err = uc_mgr_card_open(mgr);
        if (err < 0) {
                uc_mgr_free(mgr);
@@ -1402,6 +1407,8 @@ int snd_use_case_mgr_open(snd_use_case_mgr_t **uc_mgr,
        /* get info on use_cases and verify against card */
        err = import_master_config(mgr);
        if (err < 0) {
+               if (err == -ENXIO && mgr->suppress_nodev_errors)
+                       goto _err;
                uc_error("error: failed to import %s use case configuration %d",
                         card_name, err);
                goto _err;

diff --git a/src/ucm/parser.c b/src/ucm/parser.c
index ee9978000ec7bbb1c113269d85523db080830ab5..e69fd31f3c0141eafa5c36ca436f0fb8f0ad02af 100644 (file)
--- a/src/ucm/parser.c
+++ b/src/ucm/parser.c
@@ -239,7 +239,8 @@ static int error_node(snd_use_case_mgr_t *uc_mgr, snd_config_t *cfg)
                uc_error("error: failed to get Error string");
                return err;
        }
-       uc_error("%s", s);
+       if (!uc_mgr->suppress_nodev_errors)
+               uc_error("%s", s);
        free(s);
        return -ENXIO;
 }

diff --git a/src/ucm/ucm_local.h b/src/ucm/ucm_local.h
index 8eb1fc7a2f4dd7fbc555e9fd628921793e4e2f64..44791b3223b526d01046cecf2a8529b9ba90974c 100644 (file)
--- a/src/ucm/ucm_local.h
+++ b/src/ucm/ucm_local.h
@@ -227,6 +227,7 @@ struct snd_use_case_mgr {
        char *comment;
        int conf_format;
        unsigned int ucm_card_number;
+       int suppress_nodev_errors;
 
        /* UCM cards list */
        struct list_head cards_list;