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![Takashi Iwai](/assets/img/avatar_default.png)
For allowing applications to track the FB active changes, this patch adds the notification from the system port at each time a FB change is handled and the active flag or re-grouping happens. Link: https://lore.kernel.org/r/20230612081054.17200-8-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
177 lines
4.9 KiB
C
177 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ALSA sequencer System services Client
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* Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
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*/
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <sound/core.h>
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#include "seq_system.h"
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#include "seq_timer.h"
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#include "seq_queue.h"
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/* internal client that provide system services, access to timer etc. */
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/*
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* Port "Timer"
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* - send tempo /start/stop etc. events to this port to manipulate the
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* queue's timer. The queue address is specified in
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* data.queue.queue.
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* - this port supports subscription. The received timer events are
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* broadcasted to all subscribed clients. The modified tempo
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* value is stored on data.queue.value.
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* The modifier client/port is not send.
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*
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* Port "Announce"
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* - does not receive message
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* - supports supscription. For each client or port attaching to or
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* detaching from the system an announcement is send to the subscribed
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* clients.
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*
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* Idea: the subscription mechanism might also work handy for distributing
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* synchronisation and timing information. In this case we would ideally have
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* a list of subscribers for each type of sync (time, tick), for each timing
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* queue.
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*
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* NOTE: the queue to be started, stopped, etc. must be specified
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* in data.queue.addr.queue field. queue is used only for
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* scheduling, and no longer referred as affected queue.
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* They are used only for timer broadcast (see above).
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* -- iwai
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*/
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/* client id of our system client */
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static int sysclient = -1;
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/* port id numbers for this client */
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static int announce_port = -1;
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/* fill standard header data, source port & channel are filled in */
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static int setheader(struct snd_seq_event * ev, int client, int port)
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{
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if (announce_port < 0)
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return -ENODEV;
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memset(ev, 0, sizeof(struct snd_seq_event));
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ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
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ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
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ev->source.client = sysclient;
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ev->source.port = announce_port;
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ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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/* fill data */
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/*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
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ev->data.addr.client = client;
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ev->data.addr.port = port;
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return 0;
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}
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/* entry points for broadcasting system events */
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void snd_seq_system_broadcast(int client, int port, int type)
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{
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struct snd_seq_event ev;
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if (setheader(&ev, client, port) < 0)
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return;
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ev.type = type;
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snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
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}
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EXPORT_SYMBOL_GPL(snd_seq_system_broadcast);
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/* entry points for broadcasting system events */
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int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
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{
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ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
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ev->source.client = sysclient;
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ev->source.port = announce_port;
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ev->dest.client = client;
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ev->dest.port = port;
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return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
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}
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/* call-back handler for timer events */
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static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
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{
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return snd_seq_control_queue(ev, atomic, hop);
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}
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/* register our internal client */
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int __init snd_seq_system_client_init(void)
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{
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struct snd_seq_port_callback pcallbacks;
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struct snd_seq_port_info *port;
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int err;
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port = kzalloc(sizeof(*port), GFP_KERNEL);
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if (!port)
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return -ENOMEM;
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memset(&pcallbacks, 0, sizeof(pcallbacks));
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pcallbacks.owner = THIS_MODULE;
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pcallbacks.event_input = event_input_timer;
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/* register client */
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sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
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if (sysclient < 0) {
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kfree(port);
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return sysclient;
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}
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/* register timer */
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strcpy(port->name, "Timer");
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port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
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port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
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port->kernel = &pcallbacks;
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port->type = 0;
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port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
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port->addr.client = sysclient;
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port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
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err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
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port);
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if (err < 0)
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goto error_port;
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/* register announcement port */
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strcpy(port->name, "Announce");
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port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
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port->kernel = NULL;
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port->type = 0;
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port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
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port->addr.client = sysclient;
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port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
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err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
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port);
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if (err < 0)
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goto error_port;
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announce_port = port->addr.port;
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kfree(port);
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return 0;
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error_port:
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snd_seq_system_client_done();
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kfree(port);
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return err;
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}
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/* unregister our internal client */
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void snd_seq_system_client_done(void)
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{
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int oldsysclient = sysclient;
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if (oldsysclient >= 0) {
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sysclient = -1;
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announce_port = -1;
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snd_seq_delete_kernel_client(oldsysclient);
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}
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}
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