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Commit efe66bfd authored by Sriharsha Allenki's avatar Sriharsha Allenki
Browse files

usb: gadget: f_uac2: Unblock pcm read when HOST closes stream 



The pcm_read/write function which is used to read/write
from/to the pcm devices waits for the data/device even when
HOST closes the stream. And is stuck in the waiting loop for
long before it errors out. Fix this by setting the
pcm device state to SNDRV_PCM_STATE_DISCONNECTED whenever a
pcm device is open and a set alt zero happens or usb cable is
disconnected. This helps the waiting loop to error out quickly
whenever set alt zero happens or usb cable is disconnected and
thus unblocking the pcm read/write.

Change-Id: I27a8e994ff2914b0513c96d3598ac23d80398cdc
Signed-off-by: default avatarSriharsha Allenki <sallenki@codeaurora.org>
parent bd4535a8

drivers/usb/gadget/function/f_uac2.c

+30 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/workqueue.h>



#include <sound/core.h>

#include <sound/asound.h>

#include <sound/pcm.h>

#include <sound/pcm_params.h>
@@ -94,6 +95,7 @@ struct uac2_rtd_params { 
	unsigned char *dma_area;



	struct snd_pcm_substream *ss;

	bool is_pcm_open; /* For state information */



	/* Ring buffer */

	ssize_t hw_ptr;
@@ -452,6 +454,7 @@ static int uac2_pcm_open(struct snd_pcm_substream *substream) 
		runtime->hw.channels_min = num_channels(p_chmask);

		runtime->hw.period_bytes_min = 2 * uac2->p_prm.max_psize

						/ runtime->hw.periods_min;

		uac2->p_prm.is_pcm_open = 1;

	} else {

		if (audio_dev->as_out_alt == 0) {

			pr_err("%s: Host has not started the streaming\n",
@@ -487,6 +490,7 @@ static int uac2_pcm_open(struct snd_pcm_substream *substream) 
		runtime->hw.channels_min = num_channels(c_chmask);

		runtime->hw.period_bytes_min = 2 * uac2->c_prm.max_psize

						/ runtime->hw.periods_min;

		uac2->c_prm.is_pcm_open = 1;

	}



	runtime->hw.rate_max = runtime->hw.rate_min;
@@ -503,9 +507,20 @@ static int uac2_pcm_null(struct snd_pcm_substream *substream) 
	return 0;

}



static int uac2_pcm_close(struct snd_pcm_substream *substream)

{

	struct snd_uac2_chip *uac2 = snd_pcm_substream_chip(substream);



	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

		uac2->p_prm.is_pcm_open = 0;

	else

		uac2->c_prm.is_pcm_open = 0;

	return 0;

}



static struct snd_pcm_ops uac2_pcm_ops = {

	.open = uac2_pcm_open,

	.close = uac2_pcm_null,

	.close = uac2_pcm_close,

	.ioctl = snd_pcm_lib_ioctl,

	.hw_params = uac2_pcm_hw_params,

	.hw_free = uac2_pcm_hw_free,
@@ -1762,6 +1777,9 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt) 
			queue_delayed_work(agdev->uevent_wq, &agdev->c_work,

					UAC2_UEVENT_DELAY);

		} else {

			if (prm->is_pcm_open)

				snd_pcm_stop(prm->ss,

						SNDRV_PCM_STATE_DISCONNECTED);

			pr_debug("%s: scheduling disconnect c_uevent_work\n",

					__func__);

			queue_delayed_work(agdev->uevent_wq,
@@ -1802,6 +1820,9 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt) 
			queue_delayed_work(agdev->uevent_wq, &agdev->p_work,

					UAC2_UEVENT_DELAY);

		} else {

			if (prm->is_pcm_open)

				snd_pcm_stop(prm->ss,

						SNDRV_PCM_STATE_DISCONNECTED);

			pr_debug("%s: scheduling disconnect p_uevent_work\n",

					__func__);

			queue_delayed_work(agdev->uevent_wq,
@@ -1888,9 +1909,13 @@ afunc_disable(struct usb_function *fn) 
	queue_work(agdev->uevent_wq, &agdev->disconnect_work);

	free_ep(&uac2->p_prm, agdev->in_ep);

	agdev->as_in_alt = 0;

	if (uac2->p_prm.is_pcm_open)

		snd_pcm_stop(uac2->p_prm.ss, SNDRV_PCM_STATE_DISCONNECTED);



	free_ep(&uac2->c_prm, agdev->out_ep);

	agdev->as_out_alt = 0;

	if (uac2->c_prm.is_pcm_open)

		snd_pcm_stop(uac2->c_prm.ss, SNDRV_PCM_STATE_DISCONNECTED);

}



static int
@@ -2262,9 +2287,13 @@ static void afunc_unbind(struct usb_configuration *c, struct usb_function *f) 
	alsa_uac2_exit(agdev);



	prm = &agdev->uac2.p_prm;

	if (prm->is_pcm_open)

		snd_pcm_stop(prm->ss, SNDRV_PCM_STATE_DISCONNECTED);

	kfree(prm->rbuf);



	prm = &agdev->uac2.c_prm;

	if (prm->is_pcm_open)

		snd_pcm_stop(prm->ss, SNDRV_PCM_STATE_DISCONNECTED);

	kfree(prm->rbuf);

	usb_free_all_descriptors(f);