sound/usb/line6/pcm.c

Source file repositories/reference/linux-study-clean/sound/usb/line6/pcm.c

File Facts

System
Linux kernel
Corpus path
sound/usb/line6/pcm.c
Extension
.c
Size
15612 bytes
Lines
605
Domain
Driver Families
Bucket
sound/usb
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (err < 0) {
			line6pcm->impulse_volume = 0;
			return err;
		}
	} else {
		line6_pcm_release(line6pcm, LINE6_STREAM_IMPULSE);
	}
	return 1;
}

/* impulse response period controls */
static int snd_line6_impulse_period_info(struct snd_kcontrol *kcontrol,
					 struct snd_ctl_elem_info *uinfo)
{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	uinfo->count = 1;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 2000;
	return 0;
}

static int snd_line6_impulse_period_get(struct snd_kcontrol *kcontrol,
					struct snd_ctl_elem_value *ucontrol)
{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);

	ucontrol->value.integer.value[0] = line6pcm->impulse_period;
	return 0;
}

static int snd_line6_impulse_period_put(struct snd_kcontrol *kcontrol,
					struct snd_ctl_elem_value *ucontrol)
{
	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
	int value = ucontrol->value.integer.value[0];

	if (line6pcm->impulse_period == value)
		return 0;

	line6pcm->impulse_period = value;
	return 1;
}

/*
	Unlink all currently active URBs.
*/
static void line6_unlink_audio_urbs(struct snd_line6_pcm *line6pcm,
				    struct line6_pcm_stream *pcms)
{
	int i;

	for (i = 0; i < line6pcm->line6->iso_buffers; i++) {
		if (test_bit(i, &pcms->active_urbs)) {
			if (!test_and_set_bit(i, &pcms->unlink_urbs))
				usb_unlink_urb(pcms->urbs[i]);
		}
	}
}

/*
	Wait until unlinking of all currently active URBs has been finished.
*/
static void line6_wait_clear_audio_urbs(struct snd_line6_pcm *line6pcm,
					struct line6_pcm_stream *pcms)
{
	int timeout = HZ;
	int i;
	int alive;

	do {
		alive = 0;
		for (i = 0; i < line6pcm->line6->iso_buffers; i++) {
			if (test_bit(i, &pcms->active_urbs))
				alive++;
		}
		if (!alive)
			break;
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(1);
	} while (--timeout > 0);
	if (alive)
		dev_err(line6pcm->line6->ifcdev,
			"timeout: still %d active urbs..\n", alive);
}

static inline struct line6_pcm_stream *
get_stream(struct snd_line6_pcm *line6pcm, int direction)
{
	return (direction == SNDRV_PCM_STREAM_PLAYBACK) ?
		&line6pcm->out : &line6pcm->in;

Annotation

Implementation Notes