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Commit 90cfcc7c authored by Manu Gautam's avatar Manu Gautam Committed by Matt Wagantall
Browse files

usb: audio: Fix realtime voice quality issues 



Change buffer size from 8K to 2K/1K i.e. worth 64msec of data and
introduce double buffering for capture path (TX/IN) to handle under-run
condition. If it still happens then send 0s for IN/TX/capture instead
of re-sending same sample. As AUDIO driver uses 8KHz sampling rate
(i.e. 16KBps for mono/single channel), change capture EP's packetsize
to match the transfer rate i.e. 16bytes every 1msec. Also drop UL
(playback) packets incase of overruns to avoid latencies for next
data due to pending xfers.

Change-Id: I7e337e2f34cbf35370f7c4f20b4dfed5325bb9c3
Signed-off-by: default avatarManu Gautam <mgautam@codeaurora.org>
[jackp@codeaurora.org: updated to fit in with new function opts style]
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
parent 5414cade

drivers/usb/gadget/function/f_uac1.c

+34 −3
Original line number Diff line number Diff line
@@ -519,6 +519,7 @@ static void f_audio_playback_work(struct work_struct *data) 
	unsigned long flags;

	int res = 0;



	pr_debug("%s: started\n", __func__);

	spin_lock_irqsave(&audio->playback_lock, flags);

	if (list_empty(&audio->play_queue)) {

		pr_err("playback_buf is empty");
@@ -537,6 +538,7 @@ static void f_audio_playback_work(struct work_struct *data) 
		pr_err("copying failed");



	f_audio_buffer_free(play_buf);

	pr_debug("%s: Done\n", __func__);

}



static int
@@ -547,6 +549,7 @@ f_audio_playback_ep_complete(struct usb_ep *ep, struct usb_request *req) 
	struct f_audio_buf *copy_buf = audio->playback_copy_buf;

	struct f_uac1_opts *opts;

	int audio_playback_buf_size;

	unsigned long flags;

	int err;



	opts = container_of(audio->card.func.fi, struct f_uac1_opts,
@@ -560,7 +563,15 @@ f_audio_playback_ep_complete(struct usb_ep *ep, struct usb_request *req) 
	if (audio_playback_buf_size - copy_buf->actual < req->actual) {

		pr_debug("audio_playback_buf_size %d - copy_buf->actual %d, req->actual %d",

			audio_playback_buf_size, copy_buf->actual, req->actual);

		spin_lock_irqsave(&audio->playback_lock, flags);

		if (!list_empty(&audio->play_queue) &&

					opts->audio_playback_realtime) {

			pr_debug("over-runs, audio write slow.. drop the packet\n");

			f_audio_buffer_free(copy_buf);

		} else {

			list_add_tail(&copy_buf->list, &audio->play_queue);

		}

		spin_unlock_irqrestore(&audio->playback_lock, flags);

		schedule_work(&audio->playback_work);

		copy_buf = f_audio_buffer_alloc(audio_playback_buf_size);

		if (IS_ERR(copy_buf)) {
@@ -569,6 +580,8 @@ f_audio_playback_ep_complete(struct usb_ep *ep, struct usb_request *req) 
		}

	}



	pr_debug("Playback %d bytes", req->actual);



	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);

	copy_buf->actual += req->actual;

	audio->playback_copy_buf = copy_buf;
@@ -591,6 +604,15 @@ static void f_audio_capture_work(struct work_struct *data) 
	unsigned long flags;

	int res = 0;



	pr_debug("%s Started\n", __func__);

	spin_lock_irqsave(&audio->capture_lock, flags);

	if (!list_empty(&audio->capture_queue)) {

		spin_unlock_irqrestore(&audio->capture_lock, flags);

		pr_debug("%s !! buffer already filled\n", __func__);

		return;

	}

	spin_unlock_irqrestore(&audio->capture_lock, flags);



	capture_buf = f_audio_buffer_alloc(audio_capture_buf_size);

	if (capture_buf <= 0) {

		pr_err("%s: buffer alloc failed\n", __func__);
@@ -624,12 +646,18 @@ f_audio_capture_ep_complete(struct usb_ep *ep, struct usb_request *req) 
		spin_lock_irqsave(&audio->capture_lock, flags);

		if (list_empty(&audio->capture_queue)) {

			spin_unlock_irqrestore(&audio->capture_lock, flags);

			pr_debug("%s no data from Audio to send\n", __func__);

			schedule_work(&audio->capture_work);

			memset(req->buf, 0, opts->req_capture_buf_size);

			goto done;

		}

		copy_buf = list_first_entry(&audio->capture_queue,

						struct f_audio_buf, list);

		list_del(&copy_buf->list);



		if (list_empty(&audio->capture_queue))

			schedule_work(&audio->capture_work);



		audio->capture_copy_buf = copy_buf;

		spin_unlock_irqrestore(&audio->capture_lock, flags);

	}
@@ -1359,6 +1387,7 @@ UAC1_INT_ATTRIBUTE(req_playback_count); 
UAC1_INT_ATTRIBUTE(req_capture_count);

UAC1_INT_ATTRIBUTE(audio_playback_buf_size);

UAC1_INT_ATTRIBUTE(audio_capture_buf_size);

UAC1_INT_ATTRIBUTE(audio_playback_realtime);



#define UAC1_STR_ATTRIBUTE(name)					\

static ssize_t f_uac1_opts_##name##_show(struct f_uac1_opts *opts,	\
@@ -1415,6 +1444,7 @@ static struct configfs_attribute *f_uac1_attrs[] = { 
	&f_uac1_opts_req_capture_count.attr,

	&f_uac1_opts_audio_playback_buf_size.attr,

	&f_uac1_opts_audio_capture_buf_size.attr,

	&f_uac1_opts_audio_playback_realtime.attr,

	&f_uac1_opts_fn_play.attr,

	&f_uac1_opts_fn_cap.attr,

	&f_uac1_opts_fn_cntl.attr,
@@ -1460,8 +1490,9 @@ static struct usb_function_instance *f_audio_alloc_inst(void) 
	opts->req_capture_buf_size = UAC1_IN_EP_MAX_PACKET_SIZE;

	opts->req_playback_count = UAC1_REQ_COUNT;

	opts->req_capture_count = UAC1_REQ_COUNT;

	opts->audio_playback_buf_size = UAC1_AUDIO_BUF_SIZE;

	opts->audio_capture_buf_size = UAC1_AUDIO_BUF_SIZE;

	opts->audio_playback_buf_size = UAC1_AUDIO_PLAYBACK_BUF_SIZE;

	opts->audio_capture_buf_size = UAC1_AUDIO_CAPTURE_BUF_SIZE;

	opts->audio_playback_realtime = 1;

	opts->fn_play = FILE_PCM_PLAYBACK;

	opts->fn_cap = FILE_PCM_CAPTURE;

	opts->fn_cntl = FILE_CONTROL;

drivers/usb/gadget/function/u_uac1.h

+4 −2
Original line number Diff line number Diff line
@@ -27,10 +27,11 @@ 
#define FILE_PCM_CAPTURE	"/dev/snd/pcmC0D0c"

#define FILE_CONTROL		"/dev/snd/controlC0"



#define UAC1_IN_EP_MAX_PACKET_SIZE	32

#define UAC1_IN_EP_MAX_PACKET_SIZE	16

#define UAC1_OUT_EP_MAX_PACKET_SIZE	200

#define UAC1_REQ_COUNT			256

#define UAC1_AUDIO_BUF_SIZE		48000

#define UAC1_AUDIO_PLAYBACK_BUF_SIZE	(64*32)

#define UAC1_AUDIO_CAPTURE_BUF_SIZE	(64*16)



/*

 * This represents the USB side of an audio card device, managed by a USB
@@ -68,6 +69,7 @@ struct f_uac1_opts { 
	int				req_capture_count;

	int				audio_playback_buf_size;

	int				audio_capture_buf_size;

	int				audio_playback_realtime;

	char				*fn_play;

	char				*fn_cap;

	char				*fn_cntl;