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ALSA: Add kconfig to specify the max card numbers 

Currently ALSA supports up to 32 card instances when the dynamic minor
is used.  While 32 cards are usually big enough for normal use cases,
there are sometimes weird requirements with more card support.

Actually, this limitation, 32, comes from the index option, where you
can pass the bit mask to assign the card.  Other than that, we can
actually give more cards up to the minor number limits (currently 256,
which can be extended more, too).

This patch adds a new Kconfig to specify the max card numbers, and
changes a few places to accept more than 32 cards.

The only incompatibility with high card numbers would be the handling
of index option.  The index option can be still used to pass the
bitmask for card assignments, but this works only up to 32 slots.
More than 32, no bitmask style option is available but only a single
slot can be specified via index option.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2013-05-15 08:46:39 +02:00 committed by syphyr
parent d4a47fcfd2
commit 94934da81c
3 changed files with 26 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/sound/core.h
View File

@ -30,7 +30,7 @@
/* number of supported soundcards */
#ifdef CONFIG_SND_DYNAMIC_MINORS
#define SNDRV_CARDS 32
#define SNDRV_CARDS CONFIG_SND_MAX_CARDS
#else
#define SNDRV_CARDS 8 /* don't change - minor numbers */
#endif

9
sound/core/Kconfig
View File

@ -158,6 +158,15 @@ config SND_DYNAMIC_MINORS
If you are unsure about this, say N here.
config SND_MAX_CARDS
int "Max number of sound cards"
range 4 256
default 32
depends on SND_DYNAMIC_MINORS
help
Specify the max number of sound cards that can be assigned
on a single machine.
config SND_SUPPORT_OLD_API
bool "Support old ALSA API"
default y

25
sound/core/init.c
View File

@ -45,7 +45,8 @@ static LIST_HEAD(shutdown_files);
static const struct file_operations snd_shutdown_f_ops;
static unsigned int snd_cards_lock; /* locked for registering/using */
/* locked for registering/using */
static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
struct snd_card *snd_cards[SNDRV_CARDS];
EXPORT_SYMBOL(snd_cards);
@ -216,29 +217,35 @@ int snd_card_create(int idx, const char *xid,
err = 0;
mutex_lock(&snd_card_mutex);
if (idx < 0) {
for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++) {
/* idx == -1 == 0xffff means: take any free slot */
if (~snd_cards_lock & idx & 1<<idx2) {
if (idx2 < sizeof(int) && !(idx & (1U << idx2)))
continue;
if (!test_bit(idx2, snd_cards_lock)) {
if (module_slot_match(module, idx2)) {
idx = idx2;
break;
}
}
}
}
if (idx < 0) {
for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++) {
/* idx == -1 == 0xffff means: take any free slot */
if (~snd_cards_lock & idx & 1<<idx2) {
if (idx2 < sizeof(int) && !(idx & (1U << idx2)))
continue;
if (!test_bit(idx2, snd_cards_lock)) {
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))
if (test_bit(idx, snd_cards_lock))
err = -EBUSY; /* invalid */
} else if (idx >= SNDRV_CARDS)
err = -ENODEV;
@ -248,7 +255,7 @@ int snd_card_create(int idx, const char *xid,
idx, snd_ecards_limit - 1, err);
goto __error;
}
snd_cards_lock |= 1 << idx; /* lock it */
set_bit(idx, snd_cards_lock); /* lock it */
if (idx >= snd_ecards_limit)
snd_ecards_limit = idx + 1; /* increase the limit */
mutex_unlock(&snd_card_mutex);
@ -300,7 +307,7 @@ int snd_card_locked(int card)
int locked;
mutex_lock(&snd_card_mutex);
locked = snd_cards_lock & (1 << card);
locked = test_bit(card, snd_cards_lock);
mutex_unlock(&snd_card_mutex);
return locked;
}
@ -412,7 +419,7 @@ int snd_card_disconnect(struct snd_card *card)
/* phase 1: disable fops (user space) operations for ALSA API */
mutex_lock(&snd_card_mutex);
snd_cards[card->number] = NULL;
snd_cards_lock &= ~(1 << card->number);
clear_bit(card->number, snd_cards_lock);
mutex_unlock(&snd_card_mutex);
/* phase 2: replace file->f_op with special dummy operations */