Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 1357 insertions, 0 deletions

diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c
new file mode 100644
index 000000000..4f6b20ed2
--- /dev/null
+++ b/sound/usb/misc/ua101.c
@@ -0,0 +1,1357 @@
+// 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;
+	unsigned long flags;
+
+	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 */
+		spin_lock_irqsave(&ua->lock, flags);
+		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;
+		spin_unlock_irqrestore(&ua->lock, flags);
+	}
+}
+
+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 long flags;
+	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.
+	 */
+	spin_lock_irqsave(&ua->lock, flags);
+	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)) {
+			spin_unlock_irqrestore(&ua->lock, flags);
+			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;
+	}
+	spin_unlock_irqrestore(&ua->lock, flags);
+	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 long flags;
+	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;
+
+	spin_lock_irqsave(&ua->lock, flags);
+
+	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)) {
+			spin_unlock_irqrestore(&ua->lock, flags);
+			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);
+	}
+
+	spin_unlock_irqrestore(&ua->lock, flags);
+
+	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;
+	spin_lock_irq(&ua->lock);
+	INIT_LIST_HEAD(&ua->ready_playback_urbs);
+	spin_unlock_irq(&ua->lock);
+
+	/*
+	 * 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 */
+		spin_lock_irq(&ua->lock);
+		frames = ua->rate_feedback[ua->rate_feedback_start];
+		add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+		ua->rate_feedback_count--;
+		spin_unlock_irq(&ua->lock);
+		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;
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		set_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	mutex_unlock(&ua->mutex);
+	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);
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err < 0)
+		goto error;
+	err = start_usb_playback(ua);
+	if (err < 0) {
+		if (!test_bit(ALSA_CAPTURE_OPEN, &ua->states))
+			stop_usb_capture(ua);
+		goto error;
+	}
+	set_bit(ALSA_PLAYBACK_OPEN, &ua->states);
+error:
+	mutex_unlock(&ua->mutex);
+	return err;
+}
+
+static int capture_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	mutex_lock(&ua->mutex);
+	clear_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	if (!test_bit(ALSA_PLAYBACK_OPEN, &ua->states))
+		stop_usb_capture(ua);
+	mutex_unlock(&ua->mutex);
+	return 0;
+}
+
+static int playback_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	mutex_lock(&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);
+	mutex_unlock(&ua->mutex);
+	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;
+	int err;
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	mutex_unlock(&ua->mutex);
+	return err;
+}
+
+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;
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		err = start_usb_playback(ua);
+	mutex_unlock(&ua->mutex);
+	return err;
+}
+
+static int capture_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	mutex_unlock(&ua->mutex);
+	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;
+
+	mutex_lock(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		err = start_usb_playback(ua);
+	mutex_unlock(&ua->mutex);
+	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)
+{
+	unsigned long flags;
+	unsigned int pos;
+
+	spin_lock_irqsave(&ua->lock, flags);
+	pos = stream->buffer_pos;
+	spin_unlock_irqrestore(&ua->lock, flags);
+	return 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 > extralen) {
+			dev_err(&interface->dev, "descriptor overflow\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;
+	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(sizeof(*urb), GFP_KERNEL);
+			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;
+
+	mutex_lock(&ua->mutex);
+	free_stream_urbs(&ua->capture);
+	free_stream_urbs(&ua->playback);
+	mutex_unlock(&ua->mutex);
+	free_stream_buffers(ua, &ua->capture);
+	free_stream_buffers(ua, &ua->playback);
+
+	for (i = 0; i < ARRAY_SIZE(ua->intf); ++i) {
+		mutex_lock(&ua->mutex);
+		intf = ua->intf[i];
+		ua->intf[i] = NULL;
+		mutex_unlock(&ua->mutex);
+		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;
+
+	mutex_lock(&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) {
+		mutex_unlock(&devices_mutex);
+		return -ENOENT;
+	}
+	err = snd_card_new(&interface->dev,
+			   index[card_index], id[card_index], THIS_MODULE,
+			   sizeof(*ua), &card);
+	if (err < 0) {
+		mutex_unlock(&devices_mutex);
+		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";
+	strcpy(card->driver, "UA-101");
+	strcpy(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;
+	strcpy(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;
+
+	mutex_unlock(&devices_mutex);
+	return 0;
+
+probe_error:
+	free_usb_related_resources(ua, interface);
+	snd_card_free(card);
+	mutex_unlock(&devices_mutex);
+	return err;
+}
+
+static void ua101_disconnect(struct usb_interface *interface)
+{
+	struct ua101 *ua = usb_get_intfdata(interface);
+	struct list_head *midi;
+
+	if (!ua)
+		return;
+
+	mutex_lock(&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);
+	mutex_lock(&ua->mutex);
+	stop_usb_playback(ua);
+	stop_usb_capture(ua);
+	mutex_unlock(&ua->mutex);
+
+	free_usb_related_resources(ua, interface);
+
+	devices_used &= ~(1 << ua->card_index);
+
+	snd_card_free_when_closed(ua->card);
+
+	mutex_unlock(&devices_mutex);
+}
+
+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);