staging: line6: fixed ALSA/PCM interaction
The PCM subsystem in the Line6 driver is mainly used for PCM playback and
capture by ALSA, but also has other tasks, most notably providing a
low-latency software monitor for devices which don't support hardware
monitoring (e.g., the TonePort series). This patch makes ALSA "play nicely"
with the other components, i.e., prevents it from resetting the isochronous
USB transfer while other PCM tasks (software monitoring) are running.
Signed-off-by: Markus Grabner <grabner@icg.tugraz.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/line6/pcm.c b/drivers/staging/line6/pcm.c
index 68727b2..37675e6 100644
--- a/drivers/staging/line6/pcm.c
+++ b/drivers/staging/line6/pcm.c
@@ -86,17 +86,22 @@
#endif
+static bool test_flags(unsigned long flags0, unsigned long flags1,
+ unsigned long mask)
+{
+ return ((flags0 & mask) == 0) && ((flags1 & mask) != 0);
+}
+
int line6_pcm_start(struct snd_line6_pcm *line6pcm, int channels)
{
unsigned long flags_old =
__sync_fetch_and_or(&line6pcm->flags, channels);
unsigned long flags_new = flags_old | channels;
int err = 0;
-
+
line6pcm->prev_fbuf = NULL;
- if (((flags_old & MASK_CAPTURE) == 0) &&
- ((flags_new & MASK_CAPTURE) != 0)) {
+ if (test_flags(flags_old, flags_new, MASK_CAPTURE)) {
/*
Waiting for completion of active URBs in the stop handler is
a bug, we therefore report an error if capturing is restarted
@@ -105,34 +110,47 @@
if (line6pcm->active_urb_in | line6pcm->unlink_urb_in)
return -EBUSY;
+ if (!(flags_new & MASK_PCM_ALSA_CAPTURE)) {
+ err = line6_alloc_capture_buffer(line6pcm);
+
+ if (err < 0)
+ goto pcm_start_error;
+ }
+
line6pcm->count_in = 0;
line6pcm->prev_fsize = 0;
err = line6_submit_audio_in_all_urbs(line6pcm);
- if (err < 0) {
- __sync_fetch_and_and(&line6pcm->flags, ~channels);
- return err;
- }
+ if (err < 0)
+ goto pcm_start_error;
}
- if (((flags_old & MASK_PLAYBACK) == 0) &&
- ((flags_new & MASK_PLAYBACK) != 0)) {
+ if (test_flags(flags_old, flags_new, MASK_PLAYBACK)) {
/*
See comment above regarding PCM restart.
*/
if (line6pcm->active_urb_out | line6pcm->unlink_urb_out)
return -EBUSY;
+ if (!(flags_new & MASK_PCM_ALSA_PLAYBACK)) {
+ err = line6_alloc_playback_buffer(line6pcm);
+
+ if (err < 0)
+ goto pcm_start_error;
+ }
+
line6pcm->count_out = 0;
err = line6_submit_audio_out_all_urbs(line6pcm);
- if (err < 0) {
- __sync_fetch_and_and(&line6pcm->flags, ~channels);
- return err;
- }
+ if (err < 0)
+ goto pcm_start_error;
}
return 0;
+
+pcm_start_error:
+ __sync_fetch_and_and(&line6pcm->flags, ~channels);
+ return err;
}
int line6_pcm_stop(struct snd_line6_pcm *line6pcm, int channels)
@@ -141,14 +159,18 @@
__sync_fetch_and_and(&line6pcm->flags, ~channels);
unsigned long flags_new = flags_old & ~channels;
- if (((flags_old & MASK_CAPTURE) != 0) &&
- ((flags_new & MASK_CAPTURE) == 0)) {
+ if (test_flags(flags_new, flags_old, MASK_CAPTURE)) {
line6_unlink_audio_in_urbs(line6pcm);
+
+ if (!(flags_old & MASK_PCM_ALSA_CAPTURE))
+ line6_free_capture_buffer(line6pcm);
}
- if (((flags_old & MASK_PLAYBACK) != 0) &&
- ((flags_new & MASK_PLAYBACK) == 0)) {
+ if (test_flags(flags_new, flags_old, MASK_PLAYBACK)) {
line6_unlink_audio_out_urbs(line6pcm);
+
+ if (!(flags_old & MASK_PCM_ALSA_PLAYBACK))
+ line6_free_playback_buffer(line6pcm);
}
return 0;
@@ -476,18 +498,21 @@
switch (substream->stream) {
case SNDRV_PCM_STREAM_PLAYBACK:
- line6_unlink_wait_clear_audio_out_urbs(line6pcm);
+ if ((line6pcm->flags & MASK_PLAYBACK) == 0)
+ line6_unlink_wait_clear_audio_out_urbs(line6pcm);
+
break;
case SNDRV_PCM_STREAM_CAPTURE:
- line6_unlink_wait_clear_audio_in_urbs(line6pcm);
+ if ((line6pcm->flags & MASK_CAPTURE) == 0)
+ line6_unlink_wait_clear_audio_in_urbs(line6pcm);
+
break;
default:
MISSING_CASE;
}
-
if (!test_and_set_bit(BIT_PREPARED, &line6pcm->flags)) {
line6pcm->count_out = 0;
line6pcm->pos_out = 0;