ALSA: firewire-lib: Add a new function to check others' connection (b04479fb) · Commits · 戴 / test

Plug Control Registers have two fields related to the number of established connections, one is 'Broadcast connection counter' and another is 'Point-to-point connection counter'. The driver can know there are established connections or not to check these fields. This commit is for considering about JACK/FFADO streaming. Currently, when JACK/FFADO starts its streaming to the device, cmp_connection_establish() is failed expectedly. This seems to be enough but there are some devices which needs to change sampling frequency before trying to establish connections. For such devices, this functionality is needed. Signed-off-by:

Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by:

Takashi Iwai <tiwai@suse.de>

sound/firewire/cmp.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,24 @@ int cmp_connection_init(struct cmp_connection *c,
		}
		EXPORT_SYMBOL(cmp_connection_init);

		/**
		* cmp_connection_check_used - check connection is already esablished or not
		* @c: the connection manager to be checked
		*/
		int cmp_connection_check_used(struct cmp_connection c, bool used)
		{
		__be32 pcr;
		int err;

		err = snd_fw_transaction(
		c->resources.unit, TCODE_READ_QUADLET_REQUEST,
		pcr_address(c), &pcr, 4, 0);
		if (err >= 0)
		*used = (pcr & cpu_to_be32(PCR_BCAST_CONN \| PCR_P2P_CONN_MASK));
		return err;
		}
		EXPORT_SYMBOL(cmp_connection_check_used);

		/**
		* cmp_connection_destroy - free connection manager resources
		* @c: the connection manager

sound/firewire/cmp.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@ int cmp_connection_init(struct cmp_connection *connection,
		struct fw_unit *unit,
		enum cmp_direction direction,
		unsigned int pcr_index);
		int cmp_connection_check_used(struct cmp_connection connection, bool used);
		void cmp_connection_destroy(struct cmp_connection *connection);

		int cmp_connection_establish(struct cmp_connection *connection,

Admin message