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Commit 8074d104 authored by Manu Gautam's avatar Manu Gautam
Browse files

usb: gadget: audio: Queue multiple buffers for TX (capture) 



Driver is currently using only one buffer for TX. This may
cause underruns at USB hardware if interrupt threshold is
greater than or equal to bInterval. Use multiple buffers (4)
to handle this and also reduce RX buffers from 256 to 48,
i.e. ability to handle 48msec of system latency which
should be sufficient.

Change-Id: I9758aef3e88e066da28e7eb2cbc5b8c6f56d47c1
Signed-off-by: default avatarManu Gautam <mgautam@codeaurora.org>
parent 85673860

drivers/usb/gadget/function/f_uac1.c

+25 −26
Original line number Diff line number Diff line
@@ -496,7 +496,6 @@ struct f_audio { 
	struct f_audio_buf		*capture_copy_buf;

	struct work_struct		capture_work;

	struct list_head		capture_queue;

	struct usb_request		*capture_req;



	u8				alt_intf[F_AUDIO_NUM_INTERFACES];
@@ -1010,7 +1009,7 @@ static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 
	unsigned long flags;

	struct f_uac1_opts *opts;

	int req_playback_buf_size, req_playback_count, audio_playback_buf_size;

	int req_capture_buf_size;

	int req_capture_buf_size, req_capture_count;

	int i = 0, err = 0;



	DBG(cdev, "intf %d, alt %d\n", intf, alt);
@@ -1019,6 +1018,7 @@ static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 
	req_playback_buf_size = opts->req_playback_buf_size;

	req_capture_buf_size = opts->req_capture_buf_size;

	req_playback_count = opts->req_playback_count;

	req_capture_count = opts->req_capture_count;

	audio_playback_buf_size = opts->audio_playback_buf_size;



	atomic_set(&audio->online, 1);
@@ -1043,6 +1043,8 @@ static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 
			in_ep->driver_data = audio;

			audio->capture_copy_buf = 0;



			schedule_work(&audio->capture_work);

			for (i = 0; i < req_capture_count && err == 0; i++) {

				/* Allocate a write buffer */

				req = usb_ep_alloc_request(in_ep, GFP_ATOMIC);

				if (!req) {
@@ -1052,20 +1054,17 @@ static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt) 
				req->buf = kzalloc(req_capture_buf_size +

						cdev->gadget->extra_buf_alloc,

						GFP_ATOMIC);

			if (!req->buf) {

				pr_err("request buffer allocation failed\n");

				if (!req->buf)

					return -ENOMEM;

			}



				req->length = req_capture_buf_size;

				req->context = audio;

				req->complete =	f_audio_complete;

			audio->capture_req = req;

				err = usb_ep_queue(in_ep, req, GFP_ATOMIC);

				if (err)

				pr_err("Failed to queue %s req: err %d\n",

					pr_err("Failed to queue %s req,err%d\n",

						 in_ep->name, err);

			schedule_work(&audio->capture_work);

			}

		} else {

			struct f_audio_buf *capture_buf;

			usb_ep_disable(in_ep);
@@ -1562,8 +1561,8 @@ static struct usb_function_instance *f_audio_alloc_inst(void) 


	opts->req_playback_buf_size = UAC1_OUT_EP_MAX_PACKET_SIZE;

	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->req_playback_count = UAC1_OUT_REQ_COUNT;

	opts->req_capture_count = UAC1_IN_REQ_COUNT;

	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;

drivers/usb/gadget/function/u_uac1.h

+2 −1
Original line number Diff line number Diff line
@@ -29,7 +29,8 @@ 


#define UAC1_IN_EP_MAX_PACKET_SIZE	32

#define UAC1_OUT_EP_MAX_PACKET_SIZE	32

#define UAC1_REQ_COUNT			256

#define UAC1_OUT_REQ_COUNT		48

#define UAC1_IN_REQ_COUNT		 4

#define UAC1_AUDIO_PLAYBACK_BUF_SIZE	(64 * UAC1_OUT_EP_MAX_PACKET_SIZE)

#define UAC1_AUDIO_CAPTURE_BUF_SIZE	(64 * UAC1_IN_EP_MAX_PACKET_SIZE)

#define UAC1_SAMPLE_RATE		16000