linux/sound/core/seq/seq.c
Kay Sievers 03cfe6f57d ALSA: support module on-demand loading for seq and timer
If CONFIG_SND_DYNAMIC_MINORS is used, assign /dev/snd/seq and
/dev/snd/timer the usual static minors, and export specific
module aliases to generate udev module on-demand loading
instructions:

  $ cat /lib/modules/2.6.33.4-smp/modules.devname
  # Device nodes to trigger on-demand module loading.
  microcode cpu/microcode c10:184
  fuse fuse c10:229
  ppp_generic ppp c108:0
  tun net/tun c10:200
  uinput uinput c10:223
  dm_mod mapper/control c10:236
  snd_timer snd/timer c116:33
  snd_seq snd/seq c116:1

The last two lines instruct udev to create device nodes, even
when the modules are not loaded at that time.

As soon as userspace accesses any of these nodes, the in-kernel
module-loader will load the module, and the device can be used.

The header file minor calculation needed to be simplified to
make __stringify() (supports only two indirections) in
the MODULE_ALIAS macro work.

This is part of systemd's effort to get rid of unconditional
module load instructions and needless init scripts.

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2010-11-24 05:53:25 +01:00

137 lines
4.0 KiB
C

/*
* ALSA sequencer main module
* Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/seq_kernel.h>
#include "seq_clientmgr.h"
#include "seq_memory.h"
#include "seq_queue.h"
#include "seq_lock.h"
#include "seq_timer.h"
#include "seq_system.h"
#include "seq_info.h"
#include <sound/minors.h>
#include <sound/seq_device.h>
#if defined(CONFIG_SND_SEQ_DUMMY_MODULE)
int seq_client_load[15] = {[0] = SNDRV_SEQ_CLIENT_DUMMY, [1 ... 14] = -1};
#else
int seq_client_load[15] = {[0 ... 14] = -1};
#endif
int seq_default_timer_class = SNDRV_TIMER_CLASS_GLOBAL;
int seq_default_timer_sclass = SNDRV_TIMER_SCLASS_NONE;
int seq_default_timer_card = -1;
int seq_default_timer_device =
#ifdef CONFIG_SND_SEQ_HRTIMER_DEFAULT
SNDRV_TIMER_GLOBAL_HRTIMER
#elif defined(CONFIG_SND_SEQ_RTCTIMER_DEFAULT)
SNDRV_TIMER_GLOBAL_RTC
#else
SNDRV_TIMER_GLOBAL_SYSTEM
#endif
;
int seq_default_timer_subdevice = 0;
int seq_default_timer_resolution = 0; /* Hz */
MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer.");
MODULE_LICENSE("GPL");
module_param_array(seq_client_load, int, NULL, 0444);
MODULE_PARM_DESC(seq_client_load, "The numbers of global (system) clients to load through kmod.");
module_param(seq_default_timer_class, int, 0644);
MODULE_PARM_DESC(seq_default_timer_class, "The default timer class.");
module_param(seq_default_timer_sclass, int, 0644);
MODULE_PARM_DESC(seq_default_timer_sclass, "The default timer slave class.");
module_param(seq_default_timer_card, int, 0644);
MODULE_PARM_DESC(seq_default_timer_card, "The default timer card number.");
module_param(seq_default_timer_device, int, 0644);
MODULE_PARM_DESC(seq_default_timer_device, "The default timer device number.");
module_param(seq_default_timer_subdevice, int, 0644);
MODULE_PARM_DESC(seq_default_timer_subdevice, "The default timer subdevice number.");
module_param(seq_default_timer_resolution, int, 0644);
MODULE_PARM_DESC(seq_default_timer_resolution, "The default timer resolution in Hz.");
MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_SEQUENCER);
MODULE_ALIAS("devname:snd/seq");
/*
* INIT PART
*/
static int __init alsa_seq_init(void)
{
int err;
snd_seq_autoload_lock();
if ((err = client_init_data()) < 0)
goto error;
/* init memory, room for selected events */
if ((err = snd_sequencer_memory_init()) < 0)
goto error;
/* init event queues */
if ((err = snd_seq_queues_init()) < 0)
goto error;
/* register sequencer device */
if ((err = snd_sequencer_device_init()) < 0)
goto error;
/* register proc interface */
if ((err = snd_seq_info_init()) < 0)
goto error;
/* register our internal client */
if ((err = snd_seq_system_client_init()) < 0)
goto error;
error:
snd_seq_autoload_unlock();
return err;
}
static void __exit alsa_seq_exit(void)
{
/* unregister our internal client */
snd_seq_system_client_done();
/* unregister proc interface */
snd_seq_info_done();
/* delete timing queues */
snd_seq_queues_delete();
/* unregister sequencer device */
snd_sequencer_device_done();
/* release event memory */
snd_sequencer_memory_done();
}
module_init(alsa_seq_init)
module_exit(alsa_seq_exit)