262 lines
6.6 KiB
C
262 lines
6.6 KiB
C
/*
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* ALSA sequencer MIDI-through client
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* Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/moduleparam.h>
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#include <sound/core.h>
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#include "seq_clientmgr.h"
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#include <sound/initval.h>
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#include <sound/asoundef.h>
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/*
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Sequencer MIDI-through client
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This gives a simple midi-through client. All the normal input events
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are redirected to output port immediately.
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The routing can be done via aconnect program in alsa-utils.
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Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
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If you want to auto-load this module, you may add the following alias
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in your /etc/conf.modules file.
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alias snd-seq-client-62 snd-seq-dummy
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The module is loaded on demand for client 62, or /proc/asound/seq/
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is accessed. If you don't need this module to be loaded, alias
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snd-seq-client-62 as "off". This will help modprobe.
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The number of ports to be created can be specified via the module
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parameter "ports". For example, to create four ports, add the
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following option in /etc/modprobe.conf:
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option snd-seq-dummy ports=4
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The model option "duplex=1" enables duplex operation to the port.
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In duplex mode, a pair of ports are created instead of single port,
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and events are tunneled between pair-ports. For example, input to
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port A is sent to output port of another port B and vice versa.
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In duplex mode, each port has DUPLEX capability.
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*/
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MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
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MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));
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static int ports = 1;
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static int duplex;
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module_param(ports, int, 0444);
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MODULE_PARM_DESC(ports, "number of ports to be created");
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module_param(duplex, bool, 0444);
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MODULE_PARM_DESC(duplex, "create DUPLEX ports");
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struct snd_seq_dummy_port {
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int client;
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int port;
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int duplex;
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int connect;
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};
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static int my_client = -1;
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/*
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* unuse callback - send ALL_SOUNDS_OFF and RESET_CONTROLLERS events
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* to subscribers.
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* Note: this callback is called only after all subscribers are removed.
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*/
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static int
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dummy_unuse(void *private_data, struct snd_seq_port_subscribe *info)
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{
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struct snd_seq_dummy_port *p;
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int i;
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struct snd_seq_event ev;
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p = private_data;
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memset(&ev, 0, sizeof(ev));
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if (p->duplex)
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ev.source.port = p->connect;
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else
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ev.source.port = p->port;
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ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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ev.type = SNDRV_SEQ_EVENT_CONTROLLER;
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for (i = 0; i < 16; i++) {
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ev.data.control.channel = i;
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ev.data.control.param = MIDI_CTL_ALL_SOUNDS_OFF;
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snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0);
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ev.data.control.param = MIDI_CTL_RESET_CONTROLLERS;
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snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0);
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}
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return 0;
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}
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/*
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* event input callback - just redirect events to subscribers
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*/
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static int
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dummy_input(struct snd_seq_event *ev, int direct, void *private_data,
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int atomic, int hop)
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{
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struct snd_seq_dummy_port *p;
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struct snd_seq_event tmpev;
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p = private_data;
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if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
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ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
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return 0; /* ignore system messages */
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tmpev = *ev;
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if (p->duplex)
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tmpev.source.port = p->connect;
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else
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tmpev.source.port = p->port;
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tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
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}
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/*
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* free_private callback
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*/
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static void
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dummy_free(void *private_data)
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{
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kfree(private_data);
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}
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/*
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* create a port
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*/
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static struct snd_seq_dummy_port __init *
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create_port(int idx, int type)
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{
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struct snd_seq_port_info pinfo;
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struct snd_seq_port_callback pcb;
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struct snd_seq_dummy_port *rec;
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if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
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return NULL;
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rec->client = my_client;
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rec->duplex = duplex;
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rec->connect = 0;
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memset(&pinfo, 0, sizeof(pinfo));
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pinfo.addr.client = my_client;
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if (duplex)
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sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
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(type ? 'B' : 'A'));
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else
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sprintf(pinfo.name, "Midi Through Port-%d", idx);
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pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
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pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
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if (duplex)
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pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
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pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
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| SNDRV_SEQ_PORT_TYPE_SOFTWARE
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| SNDRV_SEQ_PORT_TYPE_PORT;
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memset(&pcb, 0, sizeof(pcb));
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pcb.owner = THIS_MODULE;
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pcb.unuse = dummy_unuse;
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pcb.event_input = dummy_input;
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pcb.private_free = dummy_free;
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pcb.private_data = rec;
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pinfo.kernel = &pcb;
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if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) {
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kfree(rec);
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return NULL;
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}
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rec->port = pinfo.addr.port;
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return rec;
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}
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/*
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* register client and create ports
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*/
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static int __init
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register_client(void)
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{
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struct snd_seq_dummy_port *rec1, *rec2;
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int i;
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if (ports < 1) {
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snd_printk(KERN_ERR "invalid number of ports %d\n", ports);
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return -EINVAL;
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}
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/* create client */
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my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY,
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"Midi Through");
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if (my_client < 0)
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return my_client;
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/* create ports */
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for (i = 0; i < ports; i++) {
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rec1 = create_port(i, 0);
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if (rec1 == NULL) {
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snd_seq_delete_kernel_client(my_client);
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return -ENOMEM;
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}
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if (duplex) {
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rec2 = create_port(i, 1);
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if (rec2 == NULL) {
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snd_seq_delete_kernel_client(my_client);
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return -ENOMEM;
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}
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rec1->connect = rec2->port;
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rec2->connect = rec1->port;
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}
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}
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return 0;
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}
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/*
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* delete client if exists
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*/
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static void __exit
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delete_client(void)
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{
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if (my_client >= 0)
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snd_seq_delete_kernel_client(my_client);
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}
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/*
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* Init part
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*/
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static int __init alsa_seq_dummy_init(void)
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{
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int err;
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snd_seq_autoload_lock();
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err = register_client();
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snd_seq_autoload_unlock();
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return err;
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}
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static void __exit alsa_seq_dummy_exit(void)
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{
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delete_client();
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}
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module_init(alsa_seq_dummy_init)
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module_exit(alsa_seq_dummy_exit)
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