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Commit 7bb2491b authored by Takashi Iwai's avatar Takashi Iwai
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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: default avatarTakashi Iwai <tiwai@suse.de>
parent 8edbb198

include/sound/core.h

+1 −1
Original line number Diff line number Diff line
@@ -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

sound/core/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -157,6 +157,15 @@ 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

sound/core/init.c

+16 −9
Original line number Diff line number Diff line
@@ -46,7 +46,8 @@ 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);
@@ -167,29 +168,35 @@ 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;
@@ -199,7 +206,7 @@ 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);
@@ -249,7 +256,7 @@ 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;

}
@@ -361,7 +368,7 @@ 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 */