[ALSA] Improve the slots option handling
Fix and improve the slots option handling. The sound core tries to
find the slot with the given module name first and assign if it's
still available. If all pre-given slots are unavailable, then try
to find another free slot.
Also, when a module name begins with '!', it means the negative match:
the slot will be given for any modules but that one.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index f48939e..529073d 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -2271,6 +2271,10 @@
other driver (e.g. snd-usb-audio) is loaded before snd-interwave or
snd-ens1371, it will be assigned to the third or later slot.
+When a module name is given with '!', the slot will be given for any
+modules but that name. For example, "slots=!snd-pcsp" will reserve
+the first slot for any modules but snd-pcsp.
+
ALSA PCM devices to OSS devices mapping
=======================================
diff --git a/sound/core/init.c b/sound/core/init.c
index ac05734..5c254d4 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -46,17 +46,24 @@
module_param_array(slots, charp, NULL, 0444);
MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
-/* return non-zero if the given index is already reserved for another
+/* return non-zero if the given index is reserved for the given
* module via slots option
*/
-static int module_slot_mismatch(struct module *module, int idx)
+static int module_slot_match(struct module *module, int idx)
{
+ int match = 1;
#ifdef MODULE
- char *s1, *s2;
+ const char *s1, *s2;
+
if (!module || !module->name || !slots[idx])
return 0;
- s1 = slots[idx];
- s2 = module->name;
+
+ s1 = module->name;
+ s2 = slots[idx];
+ if (*s2 == '!') {
+ match = 0; /* negative match */
+ s2++;
+ }
/* compare module name strings
* hyphens are handled as equivalent with underscore
*/
@@ -68,12 +75,12 @@
if (c2 == '-')
c2 = '_';
if (c1 != c2)
- return 1;
+ return !match;
if (!c1)
break;
}
-#endif
- return 0;
+#endif /* MODULE */
+ return match;
}
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
@@ -129,7 +136,7 @@
struct module *module, int extra_size)
{
struct snd_card *card;
- int err;
+ int err, idx2;
if (extra_size < 0)
extra_size = 0;
@@ -144,35 +151,41 @@
err = 0;
mutex_lock(&snd_card_mutex);
if (idx < 0) {
- int idx2;
for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
/* idx == -1 == 0xffff means: take any free slot */
if (~snd_cards_lock & idx & 1<<idx2) {
- if (module_slot_mismatch(module, idx2))
- continue;
- idx = idx2;
- if (idx >= snd_ecards_limit)
- snd_ecards_limit = idx + 1;
- break;
+ if (module_slot_match(module, idx2)) {
+ idx = idx2;
+ break;
+ }
}
- } else {
- if (idx < snd_ecards_limit) {
- if (snd_cards_lock & (1 << idx))
- err = -EBUSY; /* invalid */
- } else {
- if (idx < SNDRV_CARDS)
- snd_ecards_limit = idx + 1; /* increase the limit */
- else
- err = -ENODEV;
- }
}
- if (idx < 0 || err < 0) {
+ if (idx < 0) {
+ for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
+ /* idx == -1 == 0xffff means: take any free slot */
+ if (~snd_cards_lock & idx & 1<<idx2) {
+ if (!slots[idx2] || !*slots[idx2]) {
+ idx = idx2;
+ break;
+ }
+ }
+ }
+ if (idx < 0)
+ err = -ENODEV;
+ else if (idx < snd_ecards_limit) {
+ if (snd_cards_lock & (1 << idx))
+ err = -EBUSY; /* invalid */
+ } else if (idx >= SNDRV_CARDS)
+ err = -ENODEV;
+ if (err < 0) {
mutex_unlock(&snd_card_mutex);
snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
idx, snd_ecards_limit - 1, err);
goto __error;
}
snd_cards_lock |= 1 << idx; /* lock it */
+ if (idx >= snd_ecards_limit)
+ snd_ecards_limit = idx + 1; /* increase the limit */
mutex_unlock(&snd_card_mutex);
card->number = idx;
card->module = module;