git.oblomov.eu Git - linux-2.6/blob - sound/core/seq/seq_ports.c

   1 /*
   2  *   ALSA sequencer Ports
   3  *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
   4  *                         Jaroslav Kysela <perex@perex.cz>
   5  *
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; either version 2 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with this program; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  20  *
  21  */
  22
  23 #include <sound/core.h>
  24 #include <linux/slab.h>
  25 #include "seq_system.h"
  26 #include "seq_ports.h"
  27 #include "seq_clientmgr.h"
  28
  29 /*
  30
  31    registration of client ports
  32
  33  */
  34
  35
  36 /*
  37
  38 NOTE: the current implementation of the port structure as a linked list is
  39 not optimal for clients that have many ports. For sending messages to all
  40 subscribers of a port we first need to find the address of the port
  41 structure, which means we have to traverse the list. A direct access table
  42 (array) would be better, but big preallocated arrays waste memory.
  43
  44 Possible actions:
  45
  46 1) leave it this way, a client does normaly does not have more than a few
  47 ports
  48
  49 2) replace the linked list of ports by a array of pointers which is
  50 dynamicly kmalloced. When a port is added or deleted we can simply allocate
  51 a new array, copy the corresponding pointers, and delete the old one. We
  52 then only need a pointer to this array, and an integer that tells us how
  53 much elements are in array.
  54
  55 */
  56
  57 /* return pointer to port structure - port is locked if found */
  58 struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client,
  59                                                  int num)
  60 {
  61         struct snd_seq_client_port *port;
  62
  63         if (client == NULL)
  64                 return NULL;
  65         read_lock(&client->ports_lock);
  66         list_for_each_entry(port, &client->ports_list_head, list) {
  67                 if (port->addr.port == num) {
  68                         if (port->closing)
  69                                 break; /* deleting now */
  70                         snd_use_lock_use(&port->use_lock);
  71                         read_unlock(&client->ports_lock);
  72                         return port;
  73                 }
  74         }
  75         read_unlock(&client->ports_lock);
  76         return NULL;            /* not found */
  77 }
  78
  79
  80 /* search for the next port - port is locked if found */
  81 struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
  82                                                        struct snd_seq_port_info *pinfo)
  83 {
  84         int num;
  85         struct snd_seq_client_port *port, *found;
  86
  87         num = pinfo->addr.port;
  88         found = NULL;
  89         read_lock(&client->ports_lock);
  90         list_for_each_entry(port, &client->ports_list_head, list) {
  91                 if (port->addr.port < num)
  92                         continue;
  93                 if (port->addr.port == num) {
  94                         found = port;
  95                         break;
  96                 }
  97                 if (found == NULL || port->addr.port < found->addr.port)
  98                         found = port;
  99         }
 100         if (found) {
 101                 if (found->closing)
 102                         found = NULL;
 103                 else
 104                         snd_use_lock_use(&found->use_lock);
 105         }
 106         read_unlock(&client->ports_lock);
 107         return found;
 108 }
 109
 110
 111 /* initialize snd_seq_port_subs_info */
 112 static void port_subs_info_init(struct snd_seq_port_subs_info *grp)
 113 {
 114         INIT_LIST_HEAD(&grp->list_head);
 115         grp->count = 0;
 116         grp->exclusive = 0;
 117         rwlock_init(&grp->list_lock);
 118         init_rwsem(&grp->list_mutex);
 119         grp->open = NULL;
 120         grp->close = NULL;
 121 }
 122
 123
 124 /* create a port, port number is returned (-1 on failure) */
 125 struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client,
 126                                                 int port)
 127 {
 128         unsigned long flags;
 129         struct snd_seq_client_port *new_port, *p;
 130         int num = -1;
 131
 132         /* sanity check */
 133         if (snd_BUG_ON(!client))
 134                 return NULL;
 135
 136         if (client->num_ports >= SNDRV_SEQ_MAX_PORTS - 1) {
 137                 snd_printk(KERN_WARNING "too many ports for client %d\n", client->number);
 138                 return NULL;
 139         }
 140
 141         /* create a new port */
 142         new_port = kzalloc(sizeof(*new_port), GFP_KERNEL);
 143         if (! new_port) {
 144                 snd_printd("malloc failed for registering client port\n");
 145                 return NULL;    /* failure, out of memory */
 146         }
 147         /* init port data */
 148         new_port->addr.client = client->number;
 149         new_port->addr.port = -1;
 150         new_port->owner = THIS_MODULE;
 151         sprintf(new_port->name, "port-%d", num);
 152         snd_use_lock_init(&new_port->use_lock);
 153         port_subs_info_init(&new_port->c_src);
 154         port_subs_info_init(&new_port->c_dest);
 155
 156         num = port >= 0 ? port : 0;
 157         mutex_lock(&client->ports_mutex);
 158         write_lock_irqsave(&client->ports_lock, flags);
 159         list_for_each_entry(p, &client->ports_list_head, list) {
 160                 if (p->addr.port > num)
 161                         break;
 162                 if (port < 0) /* auto-probe mode */
 163                         num = p->addr.port + 1;
 164         }
 165         /* insert the new port */
 166         list_add_tail(&new_port->list, &p->list);
 167         client->num_ports++;
 168         new_port->addr.port = num;      /* store the port number in the port */
 169         write_unlock_irqrestore(&client->ports_lock, flags);
 170         mutex_unlock(&client->ports_mutex);
 171         sprintf(new_port->name, "port-%d", num);
 172
 173         return new_port;
 174 }
 175
 176 /* */
 177 enum group_type {
 178         SRC_LIST, DEST_LIST
 179 };
 180
 181 static int subscribe_port(struct snd_seq_client *client,
 182                           struct snd_seq_client_port *port,
 183                           struct snd_seq_port_subs_info *grp,
 184                           struct snd_seq_port_subscribe *info, int send_ack);
 185 static int unsubscribe_port(struct snd_seq_client *client,
 186                             struct snd_seq_client_port *port,
 187                             struct snd_seq_port_subs_info *grp,
 188                             struct snd_seq_port_subscribe *info, int send_ack);
 189
 190
 191 static struct snd_seq_client_port *get_client_port(struct snd_seq_addr *addr,
 192                                                    struct snd_seq_client **cp)
 193 {
 194         struct snd_seq_client_port *p;
 195         *cp = snd_seq_client_use_ptr(addr->client);
 196         if (*cp) {
 197                 p = snd_seq_port_use_ptr(*cp, addr->port);
 198                 if (! p) {
 199                         snd_seq_client_unlock(*cp);
 200                         *cp = NULL;
 201                 }
 202                 return p;
 203         }
 204         return NULL;
 205 }
 206
 207 /*
 208  * remove all subscribers on the list
 209  * this is called from port_delete, for each src and dest list.
 210  */
 211 static void clear_subscriber_list(struct snd_seq_client *client,
 212                                   struct snd_seq_client_port *port,
 213                                   struct snd_seq_port_subs_info *grp,
 214                                   int grptype)
 215 {
 216         struct list_head *p, *n;
 217
 218         list_for_each_safe(p, n, &grp->list_head) {
 219                 struct snd_seq_subscribers *subs;
 220                 struct snd_seq_client *c;
 221                 struct snd_seq_client_port *aport;
 222
 223                 if (grptype == SRC_LIST) {
 224                         subs = list_entry(p, struct snd_seq_subscribers, src_list);
 225                         aport = get_client_port(&subs->info.dest, &c);
 226                 } else {
 227                         subs = list_entry(p, struct snd_seq_subscribers, dest_list);
 228                         aport = get_client_port(&subs->info.sender, &c);
 229                 }
 230                 list_del(p);
 231                 unsubscribe_port(client, port, grp, &subs->info, 0);
 232                 if (!aport) {
 233                         /* looks like the connected port is being deleted.
 234                          * we decrease the counter, and when both ports are deleted
 235                          * remove the subscriber info
 236                          */
 237                         if (atomic_dec_and_test(&subs->ref_count))
 238                                 kfree(subs);
 239                 } else {
 240                         /* ok we got the connected port */
 241                         struct snd_seq_port_subs_info *agrp;
 242                         agrp = (grptype == SRC_LIST) ? &aport->c_dest : &aport->c_src;
 243                         down_write(&agrp->list_mutex);
 244                         if (grptype == SRC_LIST)
 245                                 list_del(&subs->dest_list);
 246                         else
 247                                 list_del(&subs->src_list);
 248                         up_write(&agrp->list_mutex);
 249                         unsubscribe_port(c, aport, agrp, &subs->info, 1);
 250                         kfree(subs);
 251                         snd_seq_port_unlock(aport);
 252                         snd_seq_client_unlock(c);
 253                 }
 254         }
 255 }
 256
 257 /* delete port data */
 258 static int port_delete(struct snd_seq_client *client,
 259                        struct snd_seq_client_port *port)
 260 {
 261         /* set closing flag and wait for all port access are gone */
 262         port->closing = 1;
 263         snd_use_lock_sync(&port->use_lock);
 264
 265         /* clear subscribers info */
 266         clear_subscriber_list(client, port, &port->c_src, SRC_LIST);
 267         clear_subscriber_list(client, port, &port->c_dest, DEST_LIST);
 268
 269         if (port->private_free)
 270                 port->private_free(port->private_data);
 271
 272         snd_BUG_ON(port->c_src.count != 0);
 273         snd_BUG_ON(port->c_dest.count != 0);
 274
 275         kfree(port);
 276         return 0;
 277 }
 278
 279
 280 /* delete a port with the given port id */
 281 int snd_seq_delete_port(struct snd_seq_client *client, int port)
 282 {
 283         unsigned long flags;
 284         struct snd_seq_client_port *found = NULL, *p;
 285
 286         mutex_lock(&client->ports_mutex);
 287         write_lock_irqsave(&client->ports_lock, flags);
 288         list_for_each_entry(p, &client->ports_list_head, list) {
 289                 if (p->addr.port == port) {
 290                         /* ok found.  delete from the list at first */
 291                         list_del(&p->list);
 292                         client->num_ports--;
 293                         found = p;
 294                         break;
 295                 }
 296         }
 297         write_unlock_irqrestore(&client->ports_lock, flags);
 298         mutex_unlock(&client->ports_mutex);
 299         if (found)
 300                 return port_delete(client, found);
 301         else
 302                 return -ENOENT;
 303 }
 304
 305 /* delete the all ports belonging to the given client */
 306 int snd_seq_delete_all_ports(struct snd_seq_client *client)
 307 {
 308         unsigned long flags;
 309         struct list_head deleted_list;
 310         struct snd_seq_client_port *port, *tmp;
 311
 312         /* move the port list to deleted_list, and
 313          * clear the port list in the client data.
 314          */
 315         mutex_lock(&client->ports_mutex);
 316         write_lock_irqsave(&client->ports_lock, flags);
 317         if (! list_empty(&client->ports_list_head)) {
 318                 list_add(&deleted_list, &client->ports_list_head);
 319                 list_del_init(&client->ports_list_head);
 320         } else {
 321                 INIT_LIST_HEAD(&deleted_list);
 322         }
 323         client->num_ports = 0;
 324         write_unlock_irqrestore(&client->ports_lock, flags);
 325
 326         /* remove each port in deleted_list */
 327         list_for_each_entry_safe(port, tmp, &deleted_list, list) {
 328                 list_del(&port->list);
 329                 snd_seq_system_client_ev_port_exit(port->addr.client, port->addr.port);
 330                 port_delete(client, port);
 331         }
 332         mutex_unlock(&client->ports_mutex);
 333         return 0;
 334 }
 335
 336 /* set port info fields */
 337 int snd_seq_set_port_info(struct snd_seq_client_port * port,
 338                           struct snd_seq_port_info * info)
 339 {
 340         if (snd_BUG_ON(!port || !info))
 341                 return -EINVAL;
 342
 343         /* set port name */
 344         if (info->name[0])
 345                 strlcpy(port->name, info->name, sizeof(port->name));
 346
 347         /* set capabilities */
 348         port->capability = info->capability;
 349
 350         /* get port type */
 351         port->type = info->type;
 352
 353         /* information about supported channels/voices */
 354         port->midi_channels = info->midi_channels;
 355         port->midi_voices = info->midi_voices;
 356         port->synth_voices = info->synth_voices;
 357
 358         /* timestamping */
 359         port->timestamping = (info->flags & SNDRV_SEQ_PORT_FLG_TIMESTAMP) ? 1 : 0;
 360         port->time_real = (info->flags & SNDRV_SEQ_PORT_FLG_TIME_REAL) ? 1 : 0;
 361         port->time_queue = info->time_queue;
 362
 363         return 0;
 364 }
 365
 366 /* get port info fields */
 367 int snd_seq_get_port_info(struct snd_seq_client_port * port,
 368                           struct snd_seq_port_info * info)
 369 {
 370         if (snd_BUG_ON(!port || !info))
 371                 return -EINVAL;
 372
 373         /* get port name */
 374         strlcpy(info->name, port->name, sizeof(info->name));
 375
 376         /* get capabilities */
 377         info->capability = port->capability;
 378
 379         /* get port type */
 380         info->type = port->type;
 381
 382         /* information about supported channels/voices */
 383         info->midi_channels = port->midi_channels;
 384         info->midi_voices = port->midi_voices;
 385         info->synth_voices = port->synth_voices;
 386
 387         /* get subscriber counts */
 388         info->read_use = port->c_src.count;
 389         info->write_use = port->c_dest.count;
 390
 391         /* timestamping */
 392         info->flags = 0;
 393         if (port->timestamping) {
 394                 info->flags |= SNDRV_SEQ_PORT_FLG_TIMESTAMP;
 395                 if (port->time_real)
 396                         info->flags |= SNDRV_SEQ_PORT_FLG_TIME_REAL;
 397                 info->time_queue = port->time_queue;
 398         }
 399
 400         return 0;
 401 }
 402
 403
 404
 405 /*
 406  * call callback functions (if any):
 407  * the callbacks are invoked only when the first (for connection) or
 408  * the last subscription (for disconnection) is done.  Second or later
 409  * subscription results in increment of counter, but no callback is
 410  * invoked.
 411  * This feature is useful if these callbacks are associated with
 412  * initialization or termination of devices (see seq_midi.c).
 413  *
 414  * If callback_all option is set, the callback function is invoked
 415  * at each connnection/disconnection.
 416  */
 417
 418 static int subscribe_port(struct snd_seq_client *client,
 419                           struct snd_seq_client_port *port,
 420                           struct snd_seq_port_subs_info *grp,
 421                           struct snd_seq_port_subscribe *info,
 422                           int send_ack)
 423 {
 424         int err = 0;
 425
 426         if (!try_module_get(port->owner))
 427                 return -EFAULT;
 428         grp->count++;
 429         if (grp->open && (port->callback_all || grp->count == 1)) {
 430                 err = grp->open(port->private_data, info);
 431                 if (err < 0) {
 432                         module_put(port->owner);
 433                         grp->count--;
 434                 }
 435         }
 436         if (err >= 0 && send_ack && client->type == USER_CLIENT)
 437                 snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
 438                                                    info, SNDRV_SEQ_EVENT_PORT_SUBSCRIBED);
 439
 440         return err;
 441 }
 442
 443 static int unsubscribe_port(struct snd_seq_client *client,
 444                             struct snd_seq_client_port *port,
 445                             struct snd_seq_port_subs_info *grp,
 446                             struct snd_seq_port_subscribe *info,
 447                             int send_ack)
 448 {
 449         int err = 0;
 450
 451         if (! grp->count)
 452                 return -EINVAL;
 453         grp->count--;
 454         if (grp->close && (port->callback_all || grp->count == 0))
 455                 err = grp->close(port->private_data, info);
 456         if (send_ack && client->type == USER_CLIENT)
 457                 snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
 458                                                    info, SNDRV_SEQ_EVENT_PORT_UNSUBSCRIBED);
 459         module_put(port->owner);
 460         return err;
 461 }
 462
 463
 464
 465 /* check if both addresses are identical */
 466 static inline int addr_match(struct snd_seq_addr *r, struct snd_seq_addr *s)
 467 {
 468         return (r->client == s->client) && (r->port == s->port);
 469 }
 470
 471 /* check the two subscribe info match */
 472 /* if flags is zero, checks only sender and destination addresses */
 473 static int match_subs_info(struct snd_seq_port_subscribe *r,
 474                            struct snd_seq_port_subscribe *s)
 475 {
 476         if (addr_match(&r->sender, &s->sender) &&
 477             addr_match(&r->dest, &s->dest)) {
 478                 if (r->flags && r->flags == s->flags)
 479                         return r->queue == s->queue;
 480                 else if (! r->flags)
 481                         return 1;
 482         }
 483         return 0;
 484 }
 485
 486
 487 /* connect two ports */
 488 int snd_seq_port_connect(struct snd_seq_client *connector,
 489                          struct snd_seq_client *src_client,
 490                          struct snd_seq_client_port *src_port,
 491                          struct snd_seq_client *dest_client,
 492                          struct snd_seq_client_port *dest_port,
 493                          struct snd_seq_port_subscribe *info)
 494 {
 495         struct snd_seq_port_subs_info *src = &src_port->c_src;
 496         struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
 497         struct snd_seq_subscribers *subs, *s;
 498         int err, src_called = 0;
 499         unsigned long flags;
 500         int exclusive;
 501
 502         subs = kzalloc(sizeof(*subs), GFP_KERNEL);
 503         if (! subs)
 504                 return -ENOMEM;
 505
 506         subs->info = *info;
 507         atomic_set(&subs->ref_count, 2);
 508
 509         down_write(&src->list_mutex);
 510         down_write_nested(&dest->list_mutex, SINGLE_DEPTH_NESTING);
 511
 512         exclusive = info->flags & SNDRV_SEQ_PORT_SUBS_EXCLUSIVE ? 1 : 0;
 513         err = -EBUSY;
 514         if (exclusive) {
 515                 if (! list_empty(&src->list_head) || ! list_empty(&dest->list_head))
 516                         goto __error;
 517         } else {
 518                 if (src->exclusive || dest->exclusive)
 519                         goto __error;
 520                 /* check whether already exists */
 521                 list_for_each_entry(s, &src->list_head, src_list) {
 522                         if (match_subs_info(info, &s->info))
 523                                 goto __error;
 524                 }
 525                 list_for_each_entry(s, &dest->list_head, dest_list) {
 526                         if (match_subs_info(info, &s->info))
 527                                 goto __error;
 528                 }
 529         }
 530
 531         if ((err = subscribe_port(src_client, src_port, src, info,
 532                                   connector->number != src_client->number)) < 0)
 533                 goto __error;
 534         src_called = 1;
 535
 536         if ((err = subscribe_port(dest_client, dest_port, dest, info,
 537                                   connector->number != dest_client->number)) < 0)
 538                 goto __error;
 539
 540         /* add to list */
 541         write_lock_irqsave(&src->list_lock, flags);
 542         // write_lock(&dest->list_lock); // no other lock yet
 543         list_add_tail(&subs->src_list, &src->list_head);
 544         list_add_tail(&subs->dest_list, &dest->list_head);
 545         // write_unlock(&dest->list_lock); // no other lock yet
 546         write_unlock_irqrestore(&src->list_lock, flags);
 547
 548         src->exclusive = dest->exclusive = exclusive;
 549
 550         up_write(&dest->list_mutex);
 551         up_write(&src->list_mutex);
 552         return 0;
 553
 554  __error:
 555         if (src_called)
 556                 unsubscribe_port(src_client, src_port, src, info,
 557                                  connector->number != src_client->number);
 558         kfree(subs);
 559         up_write(&dest->list_mutex);
 560         up_write(&src->list_mutex);
 561         return err;
 562 }
 563
 564
 565 /* remove the connection */
 566 int snd_seq_port_disconnect(struct snd_seq_client *connector,
 567                             struct snd_seq_client *src_client,
 568                             struct snd_seq_client_port *src_port,
 569                             struct snd_seq_client *dest_client,
 570                             struct snd_seq_client_port *dest_port,
 571                             struct snd_seq_port_subscribe *info)
 572 {
 573         struct snd_seq_port_subs_info *src = &src_port->c_src;
 574         struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
 575         struct snd_seq_subscribers *subs;
 576         int err = -ENOENT;
 577         unsigned long flags;
 578
 579         down_write(&src->list_mutex);
 580         down_write_nested(&dest->list_mutex, SINGLE_DEPTH_NESTING);
 581
 582         /* look for the connection */
 583         list_for_each_entry(subs, &src->list_head, src_list) {
 584                 if (match_subs_info(info, &subs->info)) {
 585                         write_lock_irqsave(&src->list_lock, flags);
 586                         // write_lock(&dest->list_lock);  // no lock yet
 587                         list_del(&subs->src_list);
 588                         list_del(&subs->dest_list);
 589                         // write_unlock(&dest->list_lock);
 590                         write_unlock_irqrestore(&src->list_lock, flags);
 591                         src->exclusive = dest->exclusive = 0;
 592                         unsubscribe_port(src_client, src_port, src, info,
 593                                          connector->number != src_client->number);
 594                         unsubscribe_port(dest_client, dest_port, dest, info,
 595                                          connector->number != dest_client->number);
 596                         kfree(subs);
 597                         err = 0;
 598                         break;
 599                 }
 600         }
 601
 602         up_write(&dest->list_mutex);
 603         up_write(&src->list_mutex);
 604         return err;
 605 }
 606
 607
 608 /* get matched subscriber */
 609 struct snd_seq_subscribers *snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
 610                                                           struct snd_seq_addr *dest_addr)
 611 {
 612         struct snd_seq_subscribers *s, *found = NULL;
 613
 614         down_read(&src_grp->list_mutex);
 615         list_for_each_entry(s, &src_grp->list_head, src_list) {
 616                 if (addr_match(dest_addr, &s->info.dest)) {
 617                         found = s;
 618                         break;
 619                 }
 620         }
 621         up_read(&src_grp->list_mutex);
 622         return found;
 623 }
 624
 625 /*
 626  * Attach a device driver that wants to receive events from the
 627  * sequencer.  Returns the new port number on success.
 628  * A driver that wants to receive the events converted to midi, will
 629  * use snd_seq_midisynth_register_port().
 630  */
 631 /* exported */
 632 int snd_seq_event_port_attach(int client,
 633                               struct snd_seq_port_callback *pcbp,
 634                               int cap, int type, int midi_channels,
 635                               int midi_voices, char *portname)
 636 {
 637         struct snd_seq_port_info portinfo;
 638         int  ret;
 639
 640         /* Set up the port */
 641         memset(&portinfo, 0, sizeof(portinfo));
 642         portinfo.addr.client = client;
 643         strlcpy(portinfo.name, portname ? portname : "Unamed port",
 644                 sizeof(portinfo.name));
 645
 646         portinfo.capability = cap;
 647         portinfo.type = type;
 648         portinfo.kernel = pcbp;
 649         portinfo.midi_channels = midi_channels;
 650         portinfo.midi_voices = midi_voices;
 651
 652         /* Create it */
 653         ret = snd_seq_kernel_client_ctl(client,
 654                                         SNDRV_SEQ_IOCTL_CREATE_PORT,
 655                                         &portinfo);
 656
 657         if (ret >= 0)
 658                 ret = portinfo.addr.port;
 659
 660         return ret;
 661 }
 662
 663 EXPORT_SYMBOL(snd_seq_event_port_attach);
 664
 665 /*
 666  * Detach the driver from a port.
 667  */
 668 /* exported */
 669 int snd_seq_event_port_detach(int client, int port)
 670 {
 671         struct snd_seq_port_info portinfo;
 672         int  err;
 673
 674         memset(&portinfo, 0, sizeof(portinfo));
 675         portinfo.addr.client = client;
 676         portinfo.addr.port   = port;
 677         err = snd_seq_kernel_client_ctl(client,
 678                                         SNDRV_SEQ_IOCTL_DELETE_PORT,
 679                                         &portinfo);
 680
 681         return err;
 682 }
 683
 684 EXPORT_SYMBOL(snd_seq_event_port_detach);