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authorClemens Ladisch <clemens@ladisch.de>2012-05-13 18:49:14 +0200
committerTakashi Iwai <tiwai@suse.de>2012-05-14 10:43:36 +0200
commite9148dddc3c7b6121300319c3e31f9380d459be8 (patch)
tree42ce7e28e71caaa277fee3b1d21a378f0e8b835e /sound/firewire/amdtp.c
parent76fb87894828756e069a43ce55f775a6c893a53d (diff)
ALSA: firewire-lib: flush completed packets when reading PCM position
By flushing all completed but not yet reported packets before reading the PCM hardware position, the granularity of the pointer is improved from the interrupt interval to the packet size. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/amdtp.c')
-rw-r--r--sound/firewire/amdtp.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index 3284ee9c1ec..c2685fbd736 100644
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -532,6 +532,20 @@ err_unlock:
EXPORT_SYMBOL(amdtp_out_stream_start);
/**
+ * amdtp_out_stream_pcm_pointer - get the PCM buffer position
+ * @s: the AMDTP output stream that transports the PCM data
+ *
+ * Returns the current buffer position, in frames.
+ */
+unsigned long amdtp_out_stream_pcm_pointer(struct amdtp_out_stream *s)
+{
+ fw_iso_context_flush_completions(s->context);
+
+ return ACCESS_ONCE(s->pcm_buffer_pointer);
+}
+EXPORT_SYMBOL(amdtp_out_stream_pcm_pointer);
+
+/**
* amdtp_out_stream_update - update the stream after a bus reset
* @s: the AMDTP output stream
*/