ucm: Do not fail to parse configs on cards with an empty CardComponents lists

Since the UCM profiles for all Bay- and Cherry-Trail SST cards have been
moved over to UCM2, parsing them fails with:

ALSA lib ucm_subs.c:220:(uc_mgr_get_substituted_value) variable '${CardComponents}' is not defined in this context!

This completely breaks audio support on all Bay- and Cherry-Trail devices.

This is caused by these non-SOF ASoC using cards having an empty
CardComponents list. Which in itself is fine, but is rejected by
the ucm_subs.c code. This commit changes the ucm_subs code to accept
an empty string as a valid value for CardComponents restoring audio
functionality on these boards.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/ucm/ucm_subs.c b/src/ucm/ucm_subs.c
index 00afa9e3de0eb8f2aa8a6c405ccf3424098bc068..90e395f0ab6fde2f1a243c2c7651e5a51f033870 100644 (file)
--- a/src/ucm/ucm_subs.c
+++ b/src/ucm/ucm_subs.c
@@ -25,6 +25,7 @@
  */
 
 #include "ucm_local.h"
+#include <stdbool.h>
 #include <sys/stat.h>
 #include <limits.h>
 
@@ -145,10 +146,11 @@ static char *rval_sysfs(snd_use_case_mgr_t *uc_mgr ATTRIBUTE_UNUSED, const char
        return strdup(path);
 }
 
-#define MATCH_VARIABLE(name, id, fcn)                                  \
+#define MATCH_VARIABLE(name, id, fcn, empty_ok)                                \
        if (strncmp((name), (id), sizeof(id) - 1) == 0) {               \
                rval = fcn(uc_mgr);                                     \
                idsize = sizeof(id) - 1;                                \
+               allow_empty = (empty_ok);                               \
                goto __rval;                                            \
        }
 
@@ -189,12 +191,14 @@ int uc_mgr_get_substituted_value(snd_use_case_mgr_t *uc_mgr,
 
        while (*value) {
                if (*value == '$' && *(value+1) == '{') {
-                       MATCH_VARIABLE(value, "${ConfName}", rval_conf_name);
-                       MATCH_VARIABLE(value, "${CardId}", rval_card_id);
-                       MATCH_VARIABLE(value, "${CardDriver}", rval_card_driver);
-                       MATCH_VARIABLE(value, "${CardName}", rval_card_name);
-                       MATCH_VARIABLE(value, "${CardLongName}", rval_card_longname);
-                       MATCH_VARIABLE(value, "${CardComponents}", rval_card_components);
+                       bool allow_empty = false;
+
+                       MATCH_VARIABLE(value, "${ConfName}", rval_conf_name, false);
+                       MATCH_VARIABLE(value, "${CardId}", rval_card_id, false);
+                       MATCH_VARIABLE(value, "${CardDriver}", rval_card_driver, false);
+                       MATCH_VARIABLE(value, "${CardName}", rval_card_name, false);
+                       MATCH_VARIABLE(value, "${CardLongName}", rval_card_longname, false);
+                       MATCH_VARIABLE(value, "${CardComponents}", rval_card_components, true);
                        MATCH_VARIABLE2(value, "${env:", rval_env);
                        MATCH_VARIABLE2(value, "${sys:", rval_sysfs);
                        err = -EINVAL;
@@ -208,7 +212,7 @@ int uc_mgr_get_substituted_value(snd_use_case_mgr_t *uc_mgr,
                        }
                        goto __error;
 __rval:
-                       if (rval == NULL || rval[0] == '\0') {
+                       if (rval == NULL || (!allow_empty && rval[0] == '\0')) {
                                free(rval);
                                strncpy(r, value, idsize);
                                r[idsize] = '\0';