5 files changed, 49 insertions, 0 deletions
diff --git a/sound/usb/card.h b/sound/usb/card.h
index bcb5267a02e8..23b6f23bd36a 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -92,6 +92,8 @@ struct snd_usb_endpoint {
 	unsigned char silence_value;
 	unsigned int stride;
 	int iface, alt_idx;
+	int skip_packets;		/* quirks for devices to ignore the first n packets
+					   in a stream */
 
 	spinlock_t lock;
 	struct list_head list;
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c41181202688..94b08a6087a3 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -31,6 +31,7 @@
 #include "card.h"
 #include "endpoint.h"
 #include "pcm.h"
+#include "quirks.h"
 
 #define EP_FLAG_ACTIVATED	0
 #define EP_FLAG_RUNNING		1
@@ -170,6 +171,11 @@ static void retire_inbound_urb(struct snd_usb_endpoint *ep,
 {
 	struct urb *urb = urb_ctx->urb;
 
+	if (unlikely(ep->skip_packets > 0)) {
+		ep->skip_packets--;
+		return;
+	}
+
 	if (ep->sync_slave)
 		snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
 
@@ -825,6 +831,8 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
 	ep->unlink_mask = 0;
 	ep->phase = 0;
 
+	snd_usb_endpoint_start_quirk(ep);
+
 	/*
 	 * If this endpoint has a data endpoint as implicit feedback source,
 	 * don't start the urbs here. Instead, mark them all as available,
diff --git a/sound/usb/helper.c b/sound/usb/helper.c
index 9eed8f40b179..c1db28f874c2 100644
--- a/sound/usb/helper.c
+++ b/sound/usb/helper.c
@@ -21,6 +21,7 @@
 
 #include "usbaudio.h"
 #include "helper.h"
+#include "quirks.h"
 
 /*
  * combine bytes and get an integer value
@@ -97,6 +98,10 @@ int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
 		memcpy(data, buf, size);
 		kfree(buf);
 	}
+
+	snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype,
+			      value, index, data, size);
+
 	return err;
 }
 
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 27817266867a..0f58b4b6d702 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -761,3 +761,27 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 	}
 }
 
+void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep)
+{
+	/*
+	 * "Playback Design" products send bogus feedback data at the start
+	 * of the stream. Ignore them.
+	 */
+	if ((le16_to_cpu(ep->chip->dev->descriptor.idVendor) == 0x23ba) &&
+	    ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
+		ep->skip_packets = 4;
+}
+
+void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
+			   __u8 request, __u8 requesttype, __u16 value,
+			   __u16 index, void *data, __u16 size)
+{
+	/*
+	 * "Playback Design" products need a 20ms delay after each
+	 * class compliant request
+	 */
+	if ((le16_to_cpu(dev->descriptor.idVendor) == 0x23ba) &&
+	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+		mdelay(20);
+}
+
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index 03e5e94098cd..0ca9e91067a6 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -1,6 +1,10 @@
 #ifndef __USBAUDIO_QUIRKS_H
 #define __USBAUDIO_QUIRKS_H
 
+struct audioformat;
+struct snd_usb_endpoint;
+struct snd_usb_substream;
+
 int snd_usb_create_quirk(struct snd_usb_audio *chip,
 			 struct usb_interface *iface,
 			 struct usb_driver *driver,
@@ -20,4 +24,10 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 int snd_usb_is_big_endian_format(struct snd_usb_audio *chip,
 				 struct audioformat *fp);
 
+void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep);
+
+void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
+			   __u8 request, __u8 requesttype, __u16 value,
+			   __u16 index, void *data, __u16 size);
+
 #endif /* __USBAUDIO_QUIRKS_H */