[PATCH 3/3] ALSA: usb: fine-tune Tenor error compensation value

[Daniel Mack <daniel@zonque.org>]

Users of devices affected by the Tenor feedback data error report
buffer underruns, even with the +/- 0x1.0000 quirk applied.
Compensating the error with 0xf000 instead seems to reliably fix
that issue.

See

  https://sourceforge.net/p/alsa/mailman/message/35230259/

Reported-and-tested-by: Norman Nolte <norman.nolte@gmx.net>
Reported-and-tested-by: Thomas Gresens <T.Gresens@intershop.de>
Signed-off-by: Daniel Mack <daniel@zonque.org>
---
 sound/usb/endpoint.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c317a8d..c470251 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -1174,9 +1174,9 @@ void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
 		 * by +/- 0x1.0000.
 		 */
 		if (f < ep->freqn - 0x8000)
-			f += 0x10000;
+			f += 0xf000;
 		else if (f > ep->freqn + 0x8000)
-			f -= 0x10000;
+			f -= 0xf000;
 	} else if (unlikely(ep->freqshift == INT_MIN)) {
 		/*
 		 * The first time we see a feedback value, determine its format
-- 
2.5.5