Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

2 files changed, 1340 insertions, 0 deletions

diff --git a/sound/usb/misc/Makefile b/sound/usb/misc/Makefile
new file mode 100644
index 000000000..3e9f4adc2
--- /dev/null
+++ b/sound/usb/misc/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-ua101-y := ua101.o
+obj-$(CONFIG_SND_USB_UA101) += snd-ua101.o
diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c
new file mode 100644
index 000000000..b9a62e94e
--- /dev/null
+++ b/sound/usb/misc/ua101.c
@@ -0,0 +1,1337 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Edirol UA-101/UA-1000 driver
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "../usbaudio.h"
+#include "../midi.h"
+
+MODULE_DESCRIPTION("Edirol UA-101/1000 driver");
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_LICENSE("GPL v2");
+
+/*
+ * Should not be lower than the minimum scheduling delay of the host
+ * controller.  Some Intel controllers need more than one frame; as long as
+ * that driver doesn't tell us about this, use 1.5 frames just to be sure.
+ */
+#define MIN_QUEUE_LENGTH	12
+/* Somewhat random. */
+#define MAX_QUEUE_LENGTH	30
+/*
+ * This magic value optimizes memory usage efficiency for the UA-101's packet
+ * sizes at all sample rates, taking into account the stupid cache pool sizes
+ * that usb_alloc_coherent() uses.
+ */
+#define DEFAULT_QUEUE_LENGTH	21
+
+#define MAX_PACKET_SIZE		672 /* hardware specific */
+#define MAX_MEMORY_BUFFERS	DIV_ROUND_UP(MAX_QUEUE_LENGTH, \
+					     PAGE_SIZE / MAX_PACKET_SIZE)
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
+static unsigned int queue_length = 21;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "card index");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "enable card");
+module_param(queue_length, uint, 0644);
+MODULE_PARM_DESC(queue_length, "USB queue length in microframes, "
+		 __stringify(MIN_QUEUE_LENGTH)"-"__stringify(MAX_QUEUE_LENGTH));
+
+enum {
+	INTF_PLAYBACK,
+	INTF_CAPTURE,
+	INTF_MIDI,
+
+	INTF_COUNT
+};
+
+/* bits in struct ua101::states */
+enum {
+	USB_CAPTURE_RUNNING,
+	USB_PLAYBACK_RUNNING,
+	ALSA_CAPTURE_OPEN,
+	ALSA_PLAYBACK_OPEN,
+	ALSA_CAPTURE_RUNNING,
+	ALSA_PLAYBACK_RUNNING,
+	CAPTURE_URB_COMPLETED,
+	PLAYBACK_URB_COMPLETED,
+	DISCONNECTED,
+};
+
+struct ua101 {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf[INTF_COUNT];
+	int card_index;
+	struct snd_pcm *pcm;
+	struct list_head midi_list;
+	u64 format_bit;
+	unsigned int rate;
+	unsigned int packets_per_second;
+	spinlock_t lock;
+	struct mutex mutex;
+	unsigned long states;
+
+	/* FIFO to synchronize playback rate to capture rate */
+	unsigned int rate_feedback_start;
+	unsigned int rate_feedback_count;
+	u8 rate_feedback[MAX_QUEUE_LENGTH];
+
+	struct list_head ready_playback_urbs;
+	struct work_struct playback_work;
+	wait_queue_head_t alsa_capture_wait;
+	wait_queue_head_t rate_feedback_wait;
+	wait_queue_head_t alsa_playback_wait;
+	struct ua101_stream {
+		struct snd_pcm_substream *substream;
+		unsigned int usb_pipe;
+		unsigned int channels;
+		unsigned int frame_bytes;
+		unsigned int max_packet_bytes;
+		unsigned int period_pos;
+		unsigned int buffer_pos;
+		unsigned int queue_length;
+		struct ua101_urb {
+			struct urb urb;
+			struct usb_iso_packet_descriptor iso_frame_desc[1];
+			struct list_head ready_list;
+		} *urbs[MAX_QUEUE_LENGTH];
+		struct {
+			unsigned int size;
+			void *addr;
+			dma_addr_t dma;
+		} buffers[MAX_MEMORY_BUFFERS];
+	} capture, playback;
+};
+
+static DEFINE_MUTEX(devices_mutex);
+static unsigned int devices_used;
+static struct usb_driver ua101_driver;
+
+static void abort_alsa_playback(struct ua101 *ua);
+static void abort_alsa_capture(struct ua101 *ua);
+
+static const char *usb_error_string(int err)
+{
+	switch (err) {
+	case -ENODEV:
+		return "no device";
+	case -ENOENT:
+		return "endpoint not enabled";
+	case -EPIPE:
+		return "endpoint stalled";
+	case -ENOSPC:
+		return "not enough bandwidth";
+	case -ESHUTDOWN:
+		return "device disabled";
+	case -EHOSTUNREACH:
+		return "device suspended";
+	case -EINVAL:
+	case -EAGAIN:
+	case -EFBIG:
+	case -EMSGSIZE:
+		return "internal error";
+	default:
+		return "unknown error";
+	}
+}
+
+static void abort_usb_capture(struct ua101 *ua)
+{
+	if (test_and_clear_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+		wake_up(&ua->alsa_capture_wait);
+		wake_up(&ua->rate_feedback_wait);
+	}
+}
+
+static void abort_usb_playback(struct ua101 *ua)
+{
+	if (test_and_clear_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		wake_up(&ua->alsa_playback_wait);
+}
+
+static void playback_urb_complete(struct urb *usb_urb)
+{
+	struct ua101_urb *urb = (struct ua101_urb *)usb_urb;
+	struct ua101 *ua = urb->urb.context;
+
+	if (unlikely(urb->urb.status == -ENOENT ||	/* unlinked */
+		     urb->urb.status == -ENODEV ||	/* device removed */
+		     urb->urb.status == -ECONNRESET ||	/* unlinked */
+		     urb->urb.status == -ESHUTDOWN)) {	/* device disabled */
+		abort_usb_playback(ua);
+		abort_alsa_playback(ua);
+		return;
+	}
+
+	if (test_bit(USB_PLAYBACK_RUNNING, &ua->states)) {
+		/* append URB to FIFO */
+		guard(spinlock_irqsave)(&ua->lock);
+		list_add_tail(&urb->ready_list, &ua->ready_playback_urbs);
+		if (ua->rate_feedback_count > 0)
+			queue_work(system_highpri_wq, &ua->playback_work);
+		ua->playback.substream->runtime->delay -=
+				urb->urb.iso_frame_desc[0].length /
+						ua->playback.frame_bytes;
+	}
+}
+
+static void first_playback_urb_complete(struct urb *urb)
+{
+	struct ua101 *ua = urb->context;
+
+	urb->complete = playback_urb_complete;
+	playback_urb_complete(urb);
+
+	set_bit(PLAYBACK_URB_COMPLETED, &ua->states);
+	wake_up(&ua->alsa_playback_wait);
+}
+
+/* copy data from the ALSA ring buffer into the URB buffer */
+static bool copy_playback_data(struct ua101_stream *stream, struct urb *urb,
+			       unsigned int frames)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int frame_bytes, frames1;
+	const u8 *source;
+
+	runtime = stream->substream->runtime;
+	frame_bytes = stream->frame_bytes;
+	source = runtime->dma_area + stream->buffer_pos * frame_bytes;
+	if (stream->buffer_pos + frames <= runtime->buffer_size) {
+		memcpy(urb->transfer_buffer, source, frames * frame_bytes);
+	} else {
+		/* wrap around at end of ring buffer */
+		frames1 = runtime->buffer_size - stream->buffer_pos;
+		memcpy(urb->transfer_buffer, source, frames1 * frame_bytes);
+		memcpy(urb->transfer_buffer + frames1 * frame_bytes,
+		       runtime->dma_area, (frames - frames1) * frame_bytes);
+	}
+
+	stream->buffer_pos += frames;
+	if (stream->buffer_pos >= runtime->buffer_size)
+		stream->buffer_pos -= runtime->buffer_size;
+	stream->period_pos += frames;
+	if (stream->period_pos >= runtime->period_size) {
+		stream->period_pos -= runtime->period_size;
+		return true;
+	}
+	return false;
+}
+
+static inline void add_with_wraparound(struct ua101 *ua,
+				       unsigned int *value, unsigned int add)
+{
+	*value += add;
+	if (*value >= ua->playback.queue_length)
+		*value -= ua->playback.queue_length;
+}
+
+static void playback_work(struct work_struct *work)
+{
+	struct ua101 *ua = container_of(work, struct ua101, playback_work);
+	unsigned int frames;
+	struct ua101_urb *urb;
+	bool do_period_elapsed = false;
+	int err;
+
+	if (unlikely(!test_bit(USB_PLAYBACK_RUNNING, &ua->states)))
+		return;
+
+	/*
+	 * Synchronizing the playback rate to the capture rate is done by using
+	 * the same sequence of packet sizes for both streams.
+	 * Submitting a playback URB therefore requires both a ready URB and
+	 * the size of the corresponding capture packet, i.e., both playback
+	 * and capture URBs must have been completed.  Since the USB core does
+	 * not guarantee that playback and capture complete callbacks are
+	 * called alternately, we use two FIFOs for packet sizes and read URBs;
+	 * submitting playback URBs is possible as long as both FIFOs are
+	 * nonempty.
+	 */
+	scoped_guard(spinlock_irqsave, &ua->lock) {
+		while (ua->rate_feedback_count > 0 &&
+		       !list_empty(&ua->ready_playback_urbs)) {
+			/* take packet size out of FIFO */
+			frames = ua->rate_feedback[ua->rate_feedback_start];
+			add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			ua->rate_feedback_count--;
+
+			/* take URB out of FIFO */
+			urb = list_first_entry(&ua->ready_playback_urbs,
+					       struct ua101_urb, ready_list);
+			list_del(&urb->ready_list);
+
+			/* fill packet with data or silence */
+			urb->urb.iso_frame_desc[0].length =
+				frames * ua->playback.frame_bytes;
+			if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states))
+				do_period_elapsed |= copy_playback_data(&ua->playback,
+									&urb->urb,
+									frames);
+			else
+				memset(urb->urb.transfer_buffer, 0,
+				       urb->urb.iso_frame_desc[0].length);
+
+			/* and off you go ... */
+			err = usb_submit_urb(&urb->urb, GFP_ATOMIC);
+			if (unlikely(err < 0)) {
+				abort_usb_playback(ua);
+				abort_alsa_playback(ua);
+				dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+					err, usb_error_string(err));
+				return;
+			}
+			ua->playback.substream->runtime->delay += frames;
+		}
+	}
+
+	if (do_period_elapsed)
+		snd_pcm_period_elapsed(ua->playback.substream);
+}
+
+/* copy data from the URB buffer into the ALSA ring buffer */
+static bool copy_capture_data(struct ua101_stream *stream, struct urb *urb,
+			      unsigned int frames)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int frame_bytes, frames1;
+	u8 *dest;
+
+	runtime = stream->substream->runtime;
+	frame_bytes = stream->frame_bytes;
+	dest = runtime->dma_area + stream->buffer_pos * frame_bytes;
+	if (stream->buffer_pos + frames <= runtime->buffer_size) {
+		memcpy(dest, urb->transfer_buffer, frames * frame_bytes);
+	} else {
+		/* wrap around at end of ring buffer */
+		frames1 = runtime->buffer_size - stream->buffer_pos;
+		memcpy(dest, urb->transfer_buffer, frames1 * frame_bytes);
+		memcpy(runtime->dma_area,
+		       urb->transfer_buffer + frames1 * frame_bytes,
+		       (frames - frames1) * frame_bytes);
+	}
+
+	stream->buffer_pos += frames;
+	if (stream->buffer_pos >= runtime->buffer_size)
+		stream->buffer_pos -= runtime->buffer_size;
+	stream->period_pos += frames;
+	if (stream->period_pos >= runtime->period_size) {
+		stream->period_pos -= runtime->period_size;
+		return true;
+	}
+	return false;
+}
+
+static void capture_urb_complete(struct urb *urb)
+{
+	struct ua101 *ua = urb->context;
+	struct ua101_stream *stream = &ua->capture;
+	unsigned int frames, write_ptr;
+	bool do_period_elapsed;
+	int err;
+
+	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
+		     urb->status == -ENODEV ||		/* device removed */
+		     urb->status == -ECONNRESET ||	/* unlinked */
+		     urb->status == -ESHUTDOWN))	/* device disabled */
+		goto stream_stopped;
+
+	if (urb->status >= 0 && urb->iso_frame_desc[0].status >= 0)
+		frames = urb->iso_frame_desc[0].actual_length /
+			stream->frame_bytes;
+	else
+		frames = 0;
+
+	scoped_guard(spinlock_irqsave, &ua->lock) {
+
+		if (frames > 0 && test_bit(ALSA_CAPTURE_RUNNING, &ua->states))
+			do_period_elapsed = copy_capture_data(stream, urb, frames);
+		else
+			do_period_elapsed = false;
+
+		if (test_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+			if (unlikely(err < 0)) {
+				dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+					err, usb_error_string(err));
+				goto stream_stopped;
+			}
+
+			/* append packet size to FIFO */
+			write_ptr = ua->rate_feedback_start;
+			add_with_wraparound(ua, &write_ptr, ua->rate_feedback_count);
+			ua->rate_feedback[write_ptr] = frames;
+			if (ua->rate_feedback_count < ua->playback.queue_length) {
+				ua->rate_feedback_count++;
+				if (ua->rate_feedback_count ==
+				    ua->playback.queue_length)
+					wake_up(&ua->rate_feedback_wait);
+			} else {
+				/*
+				 * Ring buffer overflow; this happens when the playback
+				 * stream is not running.  Throw away the oldest entry,
+				 * so that the playback stream, when it starts, sees
+				 * the most recent packet sizes.
+				 */
+				add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			}
+			if (test_bit(USB_PLAYBACK_RUNNING, &ua->states) &&
+			    !list_empty(&ua->ready_playback_urbs))
+				queue_work(system_highpri_wq, &ua->playback_work);
+		}
+	}
+
+	if (do_period_elapsed)
+		snd_pcm_period_elapsed(stream->substream);
+
+	return;
+
+stream_stopped:
+	abort_usb_playback(ua);
+	abort_usb_capture(ua);
+	abort_alsa_playback(ua);
+	abort_alsa_capture(ua);
+}
+
+static void first_capture_urb_complete(struct urb *urb)
+{
+	struct ua101 *ua = urb->context;
+
+	urb->complete = capture_urb_complete;
+	capture_urb_complete(urb);
+
+	set_bit(CAPTURE_URB_COMPLETED, &ua->states);
+	wake_up(&ua->alsa_capture_wait);
+}
+
+static int submit_stream_urbs(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i) {
+		int err = usb_submit_urb(&stream->urbs[i]->urb, GFP_KERNEL);
+		if (err < 0) {
+			dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+				err, usb_error_string(err));
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void kill_stream_urbs(struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i)
+		if (stream->urbs[i])
+			usb_kill_urb(&stream->urbs[i]->urb);
+}
+
+static int enable_iso_interface(struct ua101 *ua, unsigned int intf_index)
+{
+	struct usb_host_interface *alts;
+
+	alts = ua->intf[intf_index]->cur_altsetting;
+	if (alts->desc.bAlternateSetting != 1) {
+		int err = usb_set_interface(ua->dev,
+					    alts->desc.bInterfaceNumber, 1);
+		if (err < 0) {
+			dev_err(&ua->dev->dev,
+				"cannot initialize interface; error %d: %s\n",
+				err, usb_error_string(err));
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void disable_iso_interface(struct ua101 *ua, unsigned int intf_index)
+{
+	struct usb_host_interface *alts;
+
+	if (!ua->intf[intf_index])
+		return;
+
+	alts = ua->intf[intf_index]->cur_altsetting;
+	if (alts->desc.bAlternateSetting != 0) {
+		int err = usb_set_interface(ua->dev,
+					    alts->desc.bInterfaceNumber, 0);
+		if (err < 0 && !test_bit(DISCONNECTED, &ua->states))
+			dev_warn(&ua->dev->dev,
+				 "interface reset failed; error %d: %s\n",
+				 err, usb_error_string(err));
+	}
+}
+
+static void stop_usb_capture(struct ua101 *ua)
+{
+	clear_bit(USB_CAPTURE_RUNNING, &ua->states);
+
+	kill_stream_urbs(&ua->capture);
+
+	disable_iso_interface(ua, INTF_CAPTURE);
+}
+
+static int start_usb_capture(struct ua101 *ua)
+{
+	int err;
+
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+
+	if (test_bit(USB_CAPTURE_RUNNING, &ua->states))
+		return 0;
+
+	kill_stream_urbs(&ua->capture);
+
+	err = enable_iso_interface(ua, INTF_CAPTURE);
+	if (err < 0)
+		return err;
+
+	clear_bit(CAPTURE_URB_COMPLETED, &ua->states);
+	ua->capture.urbs[0]->urb.complete = first_capture_urb_complete;
+	ua->rate_feedback_start = 0;
+	ua->rate_feedback_count = 0;
+
+	set_bit(USB_CAPTURE_RUNNING, &ua->states);
+	err = submit_stream_urbs(ua, &ua->capture);
+	if (err < 0)
+		stop_usb_capture(ua);
+	return err;
+}
+
+static void stop_usb_playback(struct ua101 *ua)
+{
+	clear_bit(USB_PLAYBACK_RUNNING, &ua->states);
+
+	kill_stream_urbs(&ua->playback);
+
+	cancel_work_sync(&ua->playback_work);
+
+	disable_iso_interface(ua, INTF_PLAYBACK);
+}
+
+static int start_usb_playback(struct ua101 *ua)
+{
+	unsigned int i, frames;
+	struct urb *urb;
+	int err = 0;
+
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+
+	if (test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		return 0;
+
+	kill_stream_urbs(&ua->playback);
+	cancel_work_sync(&ua->playback_work);
+
+	err = enable_iso_interface(ua, INTF_PLAYBACK);
+	if (err < 0)
+		return err;
+
+	clear_bit(PLAYBACK_URB_COMPLETED, &ua->states);
+	ua->playback.urbs[0]->urb.complete =
+		first_playback_urb_complete;
+	scoped_guard(spinlock_irq, &ua->lock) {
+		INIT_LIST_HEAD(&ua->ready_playback_urbs);
+	}
+
+	/*
+	 * We submit the initial URBs all at once, so we have to wait for the
+	 * packet size FIFO to be full.
+	 */
+	wait_event(ua->rate_feedback_wait,
+		   ua->rate_feedback_count >= ua->playback.queue_length ||
+		   !test_bit(USB_CAPTURE_RUNNING, &ua->states) ||
+		   test_bit(DISCONNECTED, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states)) {
+		stop_usb_playback(ua);
+		return -ENODEV;
+	}
+	if (!test_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+		stop_usb_playback(ua);
+		return -EIO;
+	}
+
+	for (i = 0; i < ua->playback.queue_length; ++i) {
+		/* all initial URBs contain silence */
+		scoped_guard(spinlock_irq, &ua->lock) {
+			frames = ua->rate_feedback[ua->rate_feedback_start];
+			add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			ua->rate_feedback_count--;
+		}
+		urb = &ua->playback.urbs[i]->urb;
+		urb->iso_frame_desc[0].length =
+			frames * ua->playback.frame_bytes;
+		memset(urb->transfer_buffer, 0,
+		       urb->iso_frame_desc[0].length);
+	}
+
+	set_bit(USB_PLAYBACK_RUNNING, &ua->states);
+	err = submit_stream_urbs(ua, &ua->playback);
+	if (err < 0)
+		stop_usb_playback(ua);
+	return err;
+}
+
+static void abort_alsa_capture(struct ua101 *ua)
+{
+	if (test_bit(ALSA_CAPTURE_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->capture.substream);
+}
+
+static void abort_alsa_playback(struct ua101 *ua)
+{
+	if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->playback.substream);
+}
+
+static int set_stream_hw(struct ua101 *ua, struct snd_pcm_substream *substream,
+			 unsigned int channels)
+{
+	int err;
+
+	substream->runtime->hw.info =
+		SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BATCH |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		SNDRV_PCM_INFO_FIFO_IN_FRAMES;
+	substream->runtime->hw.formats = ua->format_bit;
+	substream->runtime->hw.rates = snd_pcm_rate_to_rate_bit(ua->rate);
+	substream->runtime->hw.rate_min = ua->rate;
+	substream->runtime->hw.rate_max = ua->rate;
+	substream->runtime->hw.channels_min = channels;
+	substream->runtime->hw.channels_max = channels;
+	substream->runtime->hw.buffer_bytes_max = 45000 * 1024;
+	substream->runtime->hw.period_bytes_min = 1;
+	substream->runtime->hw.period_bytes_max = UINT_MAX;
+	substream->runtime->hw.periods_min = 2;
+	substream->runtime->hw.periods_max = UINT_MAX;
+	err = snd_pcm_hw_constraint_minmax(substream->runtime,
+					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+					   1500000 / ua->packets_per_second,
+					   UINT_MAX);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_constraint_msbits(substream->runtime, 0, 32, 24);
+	return err;
+}
+
+static int capture_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	ua->capture.substream = substream;
+	err = set_stream_hw(ua, substream, ua->capture.channels);
+	if (err < 0)
+		return err;
+	substream->runtime->hw.fifo_size =
+		DIV_ROUND_CLOSEST(ua->rate, ua->packets_per_second);
+	substream->runtime->delay = substream->runtime->hw.fifo_size;
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		set_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	return err;
+}
+
+static int playback_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	ua->playback.substream = substream;
+	err = set_stream_hw(ua, substream, ua->playback.channels);
+	if (err < 0)
+		return err;
+	substream->runtime->hw.fifo_size =
+		DIV_ROUND_CLOSEST(ua->rate * ua->playback.queue_length,
+				  ua->packets_per_second);
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err < 0)
+		return err;
+	err = start_usb_playback(ua);
+	if (err < 0) {
+		if (!test_bit(ALSA_CAPTURE_OPEN, &ua->states))
+			stop_usb_capture(ua);
+		return err;
+	}
+	set_bit(ALSA_PLAYBACK_OPEN, &ua->states);
+	return 0;
+}
+
+static int capture_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	clear_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	if (!test_bit(ALSA_PLAYBACK_OPEN, &ua->states))
+		stop_usb_capture(ua);
+	return 0;
+}
+
+static int playback_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	stop_usb_playback(ua);
+	clear_bit(ALSA_PLAYBACK_OPEN, &ua->states);
+	if (!test_bit(ALSA_CAPTURE_OPEN, &ua->states))
+		stop_usb_capture(ua);
+	return 0;
+}
+
+static int capture_pcm_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *hw_params)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	return start_usb_capture(ua);
+}
+
+static int playback_pcm_hw_params(struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params *hw_params)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		err = start_usb_playback(ua);
+	return err;
+}
+
+static int capture_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	scoped_guard(mutex, &ua->mutex) {
+		err = start_usb_capture(ua);
+	}
+	if (err < 0)
+		return err;
+
+	/*
+	 * The EHCI driver schedules the first packet of an iso stream at 10 ms
+	 * in the future, i.e., no data is actually captured for that long.
+	 * Take the wait here so that the stream is known to be actually
+	 * running when the start trigger has been called.
+	 */
+	wait_event(ua->alsa_capture_wait,
+		   test_bit(CAPTURE_URB_COMPLETED, &ua->states) ||
+		   !test_bit(USB_CAPTURE_RUNNING, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+	if (!test_bit(USB_CAPTURE_RUNNING, &ua->states))
+		return -EIO;
+
+	ua->capture.period_pos = 0;
+	ua->capture.buffer_pos = 0;
+	return 0;
+}
+
+static int playback_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	scoped_guard(mutex, &ua->mutex) {
+		err = start_usb_capture(ua);
+		if (err >= 0)
+			err = start_usb_playback(ua);
+	}
+	if (err < 0)
+		return err;
+
+	/* see the comment in capture_pcm_prepare() */
+	wait_event(ua->alsa_playback_wait,
+		   test_bit(PLAYBACK_URB_COMPLETED, &ua->states) ||
+		   !test_bit(USB_PLAYBACK_RUNNING, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+	if (!test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		return -EIO;
+
+	substream->runtime->delay = 0;
+	ua->playback.period_pos = 0;
+	ua->playback.buffer_pos = 0;
+	return 0;
+}
+
+static int capture_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct ua101 *ua = substream->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		if (!test_bit(USB_CAPTURE_RUNNING, &ua->states))
+			return -EIO;
+		set_bit(ALSA_CAPTURE_RUNNING, &ua->states);
+		return 0;
+	case SNDRV_PCM_TRIGGER_STOP:
+		clear_bit(ALSA_CAPTURE_RUNNING, &ua->states);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int playback_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct ua101 *ua = substream->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		if (!test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+			return -EIO;
+		set_bit(ALSA_PLAYBACK_RUNNING, &ua->states);
+		return 0;
+	case SNDRV_PCM_TRIGGER_STOP:
+		clear_bit(ALSA_PLAYBACK_RUNNING, &ua->states);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static inline snd_pcm_uframes_t ua101_pcm_pointer(struct ua101 *ua,
+						  struct ua101_stream *stream)
+{
+	guard(spinlock_irqsave)(&ua->lock);
+	return stream->buffer_pos;
+}
+
+static snd_pcm_uframes_t capture_pcm_pointer(struct snd_pcm_substream *subs)
+{
+	struct ua101 *ua = subs->private_data;
+
+	return ua101_pcm_pointer(ua, &ua->capture);
+}
+
+static snd_pcm_uframes_t playback_pcm_pointer(struct snd_pcm_substream *subs)
+{
+	struct ua101 *ua = subs->private_data;
+
+	return ua101_pcm_pointer(ua, &ua->playback);
+}
+
+static const struct snd_pcm_ops capture_pcm_ops = {
+	.open = capture_pcm_open,
+	.close = capture_pcm_close,
+	.hw_params = capture_pcm_hw_params,
+	.prepare = capture_pcm_prepare,
+	.trigger = capture_pcm_trigger,
+	.pointer = capture_pcm_pointer,
+};
+
+static const struct snd_pcm_ops playback_pcm_ops = {
+	.open = playback_pcm_open,
+	.close = playback_pcm_close,
+	.hw_params = playback_pcm_hw_params,
+	.prepare = playback_pcm_prepare,
+	.trigger = playback_pcm_trigger,
+	.pointer = playback_pcm_pointer,
+};
+
+static const struct uac_format_type_i_discrete_descriptor *
+find_format_descriptor(struct usb_interface *interface)
+{
+	struct usb_host_interface *alt;
+	u8 *extra;
+	int extralen;
+
+	if (interface->num_altsetting != 2) {
+		dev_err(&interface->dev, "invalid num_altsetting\n");
+		return NULL;
+	}
+
+	alt = &interface->altsetting[0];
+	if (alt->desc.bNumEndpoints != 0) {
+		dev_err(&interface->dev, "invalid bNumEndpoints\n");
+		return NULL;
+	}
+
+	alt = &interface->altsetting[1];
+	if (alt->desc.bNumEndpoints != 1) {
+		dev_err(&interface->dev, "invalid bNumEndpoints\n");
+		return NULL;
+	}
+
+	extra = alt->extra;
+	extralen = alt->extralen;
+	while (extralen >= sizeof(struct usb_descriptor_header)) {
+		struct uac_format_type_i_discrete_descriptor *desc;
+
+		desc = (struct uac_format_type_i_discrete_descriptor *)extra;
+		if (desc->bLength < sizeof(struct usb_descriptor_header) ||
+		    desc->bLength > extralen) {
+			dev_err(&interface->dev, "invalid descriptor length\n");
+			return NULL;
+		}
+		if (desc->bLength == UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1) &&
+		    desc->bDescriptorType == USB_DT_CS_INTERFACE &&
+		    desc->bDescriptorSubtype == UAC_FORMAT_TYPE) {
+			if (desc->bFormatType != UAC_FORMAT_TYPE_I_PCM ||
+			    desc->bSamFreqType != 1) {
+				dev_err(&interface->dev,
+					"invalid format type\n");
+				return NULL;
+			}
+			return desc;
+		}
+		extralen -= desc->bLength;
+		extra += desc->bLength;
+	}
+	dev_err(&interface->dev, "sample format descriptor not found\n");
+	return NULL;
+}
+
+static int detect_usb_format(struct ua101 *ua)
+{
+	const struct uac_format_type_i_discrete_descriptor *fmt_capture;
+	const struct uac_format_type_i_discrete_descriptor *fmt_playback;
+	const struct usb_endpoint_descriptor *epd;
+	unsigned int rate2;
+
+	fmt_capture = find_format_descriptor(ua->intf[INTF_CAPTURE]);
+	fmt_playback = find_format_descriptor(ua->intf[INTF_PLAYBACK]);
+	if (!fmt_capture || !fmt_playback)
+		return -ENXIO;
+
+	switch (fmt_capture->bSubframeSize) {
+	case 3:
+		ua->format_bit = SNDRV_PCM_FMTBIT_S24_3LE;
+		break;
+	case 4:
+		ua->format_bit = SNDRV_PCM_FMTBIT_S32_LE;
+		break;
+	default:
+		dev_err(&ua->dev->dev, "sample width is not 24 or 32 bits\n");
+		return -ENXIO;
+	}
+	if (fmt_capture->bSubframeSize != fmt_playback->bSubframeSize) {
+		dev_err(&ua->dev->dev,
+			"playback/capture sample widths do not match\n");
+		return -ENXIO;
+	}
+
+	if (fmt_capture->bBitResolution != 24 ||
+	    fmt_playback->bBitResolution != 24) {
+		dev_err(&ua->dev->dev, "sample width is not 24 bits\n");
+		return -ENXIO;
+	}
+
+	ua->rate = combine_triple(fmt_capture->tSamFreq[0]);
+	rate2 = combine_triple(fmt_playback->tSamFreq[0]);
+	if (ua->rate != rate2) {
+		dev_err(&ua->dev->dev,
+			"playback/capture rates do not match: %u/%u\n",
+			rate2, ua->rate);
+		return -ENXIO;
+	}
+
+	switch (ua->dev->speed) {
+	case USB_SPEED_FULL:
+		ua->packets_per_second = 1000;
+		break;
+	case USB_SPEED_HIGH:
+		ua->packets_per_second = 8000;
+		break;
+	default:
+		dev_err(&ua->dev->dev, "unknown device speed\n");
+		return -ENXIO;
+	}
+
+	ua->capture.channels = fmt_capture->bNrChannels;
+	ua->playback.channels = fmt_playback->bNrChannels;
+	if (!ua->capture.channels || !ua->playback.channels) {
+		dev_err(&ua->dev->dev,
+			"invalid channel count: capture %u, playback %u\n",
+			ua->capture.channels, ua->playback.channels);
+		return -EINVAL;
+	}
+
+	ua->capture.frame_bytes =
+		fmt_capture->bSubframeSize * ua->capture.channels;
+	ua->playback.frame_bytes =
+		fmt_playback->bSubframeSize * ua->playback.channels;
+
+	epd = &ua->intf[INTF_CAPTURE]->altsetting[1].endpoint[0].desc;
+	if (!usb_endpoint_is_isoc_in(epd) || usb_endpoint_maxp(epd) == 0) {
+		dev_err(&ua->dev->dev, "invalid capture endpoint\n");
+		return -ENXIO;
+	}
+	ua->capture.usb_pipe = usb_rcvisocpipe(ua->dev, usb_endpoint_num(epd));
+	ua->capture.max_packet_bytes = usb_endpoint_maxp(epd);
+
+	epd = &ua->intf[INTF_PLAYBACK]->altsetting[1].endpoint[0].desc;
+	if (!usb_endpoint_is_isoc_out(epd) || usb_endpoint_maxp(epd) == 0) {
+		dev_err(&ua->dev->dev, "invalid playback endpoint\n");
+		return -ENXIO;
+	}
+	ua->playback.usb_pipe = usb_sndisocpipe(ua->dev, usb_endpoint_num(epd));
+	ua->playback.max_packet_bytes = usb_endpoint_maxp(epd);
+	return 0;
+}
+
+static int alloc_stream_buffers(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int remaining_packets, packets, packets_per_page, i;
+	size_t size;
+
+	stream->queue_length = queue_length;
+	stream->queue_length = max(stream->queue_length,
+				   (unsigned int)MIN_QUEUE_LENGTH);
+	stream->queue_length = min(stream->queue_length,
+				   (unsigned int)MAX_QUEUE_LENGTH);
+
+	/*
+	 * The cache pool sizes used by usb_alloc_coherent() (128, 512, 2048) are
+	 * quite bad when used with the packet sizes of this device (e.g. 280,
+	 * 520, 624).  Therefore, we allocate and subdivide entire pages, using
+	 * a smaller buffer only for the last chunk.
+	 */
+	remaining_packets = stream->queue_length;
+	packets_per_page = PAGE_SIZE / stream->max_packet_bytes;
+	for (i = 0; i < ARRAY_SIZE(stream->buffers); ++i) {
+		packets = min(remaining_packets, packets_per_page);
+		size = packets * stream->max_packet_bytes;
+		stream->buffers[i].addr =
+			usb_alloc_coherent(ua->dev, size, GFP_KERNEL,
+					   &stream->buffers[i].dma);
+		if (!stream->buffers[i].addr)
+			return -ENOMEM;
+		stream->buffers[i].size = size;
+		remaining_packets -= packets;
+		if (!remaining_packets)
+			break;
+	}
+	if (remaining_packets) {
+		dev_err(&ua->dev->dev, "too many packets\n");
+		return -ENXIO;
+	}
+	return 0;
+}
+
+static void free_stream_buffers(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(stream->buffers); ++i)
+		usb_free_coherent(ua->dev,
+				  stream->buffers[i].size,
+				  stream->buffers[i].addr,
+				  stream->buffers[i].dma);
+}
+
+static int alloc_stream_urbs(struct ua101 *ua, struct ua101_stream *stream,
+			     void (*urb_complete)(struct urb *))
+{
+	unsigned max_packet_size = stream->max_packet_bytes;
+	struct ua101_urb *urb;
+	unsigned int b, u = 0;
+
+	for (b = 0; b < ARRAY_SIZE(stream->buffers); ++b) {
+		unsigned int size = stream->buffers[b].size;
+		u8 *addr = stream->buffers[b].addr;
+		dma_addr_t dma = stream->buffers[b].dma;
+
+		while (size >= max_packet_size) {
+			if (u >= stream->queue_length)
+				goto bufsize_error;
+			urb = kmalloc_obj(*urb);
+			if (!urb)
+				return -ENOMEM;
+			usb_init_urb(&urb->urb);
+			urb->urb.dev = ua->dev;
+			urb->urb.pipe = stream->usb_pipe;
+			urb->urb.transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+			urb->urb.transfer_buffer = addr;
+			urb->urb.transfer_dma = dma;
+			urb->urb.transfer_buffer_length = max_packet_size;
+			urb->urb.number_of_packets = 1;
+			urb->urb.interval = 1;
+			urb->urb.context = ua;
+			urb->urb.complete = urb_complete;
+			urb->urb.iso_frame_desc[0].offset = 0;
+			urb->urb.iso_frame_desc[0].length = max_packet_size;
+			stream->urbs[u++] = urb;
+			size -= max_packet_size;
+			addr += max_packet_size;
+			dma += max_packet_size;
+		}
+	}
+	if (u == stream->queue_length)
+		return 0;
+bufsize_error:
+	dev_err(&ua->dev->dev, "internal buffer size error\n");
+	return -ENXIO;
+}
+
+static void free_stream_urbs(struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i) {
+		kfree(stream->urbs[i]);
+		stream->urbs[i] = NULL;
+	}
+}
+
+static void free_usb_related_resources(struct ua101 *ua,
+				       struct usb_interface *interface)
+{
+	unsigned int i;
+	struct usb_interface *intf;
+
+	scoped_guard(mutex, &ua->mutex) {
+		free_stream_urbs(&ua->capture);
+		free_stream_urbs(&ua->playback);
+	}
+	free_stream_buffers(ua, &ua->capture);
+	free_stream_buffers(ua, &ua->playback);
+
+	for (i = 0; i < ARRAY_SIZE(ua->intf); ++i) {
+		scoped_guard(mutex, &ua->mutex) {
+			intf = ua->intf[i];
+			ua->intf[i] = NULL;
+		}
+		if (intf) {
+			usb_set_intfdata(intf, NULL);
+			if (intf != interface)
+				usb_driver_release_interface(&ua101_driver,
+							     intf);
+		}
+	}
+}
+
+static void ua101_card_free(struct snd_card *card)
+{
+	struct ua101 *ua = card->private_data;
+
+	mutex_destroy(&ua->mutex);
+}
+
+static int ua101_probe(struct usb_interface *interface,
+		       const struct usb_device_id *usb_id)
+{
+	static const struct snd_usb_midi_endpoint_info midi_ep = {
+		.out_cables = 0x0001,
+		.in_cables = 0x0001
+	};
+	static const struct snd_usb_audio_quirk midi_quirk = {
+		.type = QUIRK_MIDI_FIXED_ENDPOINT,
+		.data = &midi_ep
+	};
+	static const int intf_numbers[2][3] = {
+		{	/* UA-101 */
+			[INTF_PLAYBACK] = 0,
+			[INTF_CAPTURE] = 1,
+			[INTF_MIDI] = 2,
+		},
+		{	/* UA-1000 */
+			[INTF_CAPTURE] = 1,
+			[INTF_PLAYBACK] = 2,
+			[INTF_MIDI] = 3,
+		},
+	};
+	struct snd_card *card;
+	struct ua101 *ua;
+	unsigned int card_index, i;
+	int is_ua1000;
+	const char *name;
+	char usb_path[32];
+	int err;
+
+	is_ua1000 = usb_id->idProduct == 0x0044;
+
+	if (interface->altsetting->desc.bInterfaceNumber !=
+	    intf_numbers[is_ua1000][0])
+		return -ENODEV;
+
+	guard(mutex)(&devices_mutex);
+
+	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
+		if (enable[card_index] && !(devices_used & (1 << card_index)))
+			break;
+	if (card_index >= SNDRV_CARDS)
+		return -ENOENT;
+	err = snd_card_new(&interface->dev,
+			   index[card_index], id[card_index], THIS_MODULE,
+			   sizeof(*ua), &card);
+	if (err < 0)
+		return err;
+	card->private_free = ua101_card_free;
+	ua = card->private_data;
+	ua->dev = interface_to_usbdev(interface);
+	ua->card = card;
+	ua->card_index = card_index;
+	INIT_LIST_HEAD(&ua->midi_list);
+	spin_lock_init(&ua->lock);
+	mutex_init(&ua->mutex);
+	INIT_LIST_HEAD(&ua->ready_playback_urbs);
+	INIT_WORK(&ua->playback_work, playback_work);
+	init_waitqueue_head(&ua->alsa_capture_wait);
+	init_waitqueue_head(&ua->rate_feedback_wait);
+	init_waitqueue_head(&ua->alsa_playback_wait);
+
+	ua->intf[0] = interface;
+	for (i = 1; i < ARRAY_SIZE(ua->intf); ++i) {
+		ua->intf[i] = usb_ifnum_to_if(ua->dev,
+					      intf_numbers[is_ua1000][i]);
+		if (!ua->intf[i]) {
+			dev_err(&ua->dev->dev, "interface %u not found\n",
+				intf_numbers[is_ua1000][i]);
+			err = -ENXIO;
+			goto probe_error;
+		}
+		err = usb_driver_claim_interface(&ua101_driver,
+						 ua->intf[i], ua);
+		if (err < 0) {
+			ua->intf[i] = NULL;
+			err = -EBUSY;
+			goto probe_error;
+		}
+	}
+
+	err = detect_usb_format(ua);
+	if (err < 0)
+		goto probe_error;
+
+	name = usb_id->idProduct == 0x0044 ? "UA-1000" : "UA-101";
+	strscpy(card->driver, "UA-101");
+	strscpy(card->shortname, name);
+	usb_make_path(ua->dev, usb_path, sizeof(usb_path));
+	snprintf(ua->card->longname, sizeof(ua->card->longname),
+		 "EDIROL %s (serial %s), %u Hz at %s, %s speed", name,
+		 ua->dev->serial ? ua->dev->serial : "?", ua->rate, usb_path,
+		 ua->dev->speed == USB_SPEED_HIGH ? "high" : "full");
+
+	err = alloc_stream_buffers(ua, &ua->capture);
+	if (err < 0)
+		goto probe_error;
+	err = alloc_stream_buffers(ua, &ua->playback);
+	if (err < 0)
+		goto probe_error;
+
+	err = alloc_stream_urbs(ua, &ua->capture, capture_urb_complete);
+	if (err < 0)
+		goto probe_error;
+	err = alloc_stream_urbs(ua, &ua->playback, playback_urb_complete);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_pcm_new(card, name, 0, 1, 1, &ua->pcm);
+	if (err < 0)
+		goto probe_error;
+	ua->pcm->private_data = ua;
+	strscpy(ua->pcm->name, name);
+	snd_pcm_set_ops(ua->pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_pcm_ops);
+	snd_pcm_set_ops(ua->pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_pcm_ops);
+	snd_pcm_set_managed_buffer_all(ua->pcm, SNDRV_DMA_TYPE_VMALLOC,
+				       NULL, 0, 0);
+
+	err = snd_usbmidi_create(card, ua->intf[INTF_MIDI],
+				 &ua->midi_list, &midi_quirk);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+
+	usb_set_intfdata(interface, ua);
+	devices_used |= 1 << card_index;
+
+	return 0;
+
+probe_error:
+	free_usb_related_resources(ua, interface);
+	snd_card_free(card);
+	return err;
+}
+
+static void ua101_disconnect(struct usb_interface *interface)
+{
+	struct ua101 *ua = usb_get_intfdata(interface);
+	struct list_head *midi;
+
+	if (!ua)
+		return;
+
+	guard(mutex)(&devices_mutex);
+
+	set_bit(DISCONNECTED, &ua->states);
+	wake_up(&ua->rate_feedback_wait);
+
+	/* make sure that userspace cannot create new requests */
+	snd_card_disconnect(ua->card);
+
+	/* make sure that there are no pending USB requests */
+	list_for_each(midi, &ua->midi_list)
+		snd_usbmidi_disconnect(midi);
+	abort_alsa_playback(ua);
+	abort_alsa_capture(ua);
+	scoped_guard(mutex, &ua->mutex) {
+		stop_usb_playback(ua);
+		stop_usb_capture(ua);
+	}
+
+	free_usb_related_resources(ua, interface);
+
+	devices_used &= ~(1 << ua->card_index);
+
+	snd_card_free_when_closed(ua->card);
+}
+
+static const struct usb_device_id ua101_ids[] = {
+	{ USB_DEVICE(0x0582, 0x0044) }, /* UA-1000 high speed */
+	{ USB_DEVICE(0x0582, 0x007d) }, /* UA-101 high speed */
+	{ USB_DEVICE(0x0582, 0x008d) }, /* UA-101 full speed */
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, ua101_ids);
+
+static struct usb_driver ua101_driver = {
+	.name = "snd-ua101",
+	.id_table = ua101_ids,
+	.probe = ua101_probe,
+	.disconnect = ua101_disconnect,
+#if 0
+	.suspend = ua101_suspend,
+	.resume = ua101_resume,
+#endif
+};
+
+module_usb_driver(ua101_driver);