From 5e8e7c38533a8f86626e9410fa38f5854a6959df Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <clemens@ladisch.de>
Date: Mon, 10 Aug 2009 10:05:23 +0200
Subject: sound: fix OSS MIDI output data loss

In the 2.1.6 kernel, the output loop in midi_poll() was changed to
enable interrupts during the outputc() call.  Unfortunately, the check
whether the device has accepted the current byte ("ok") was moved behind
the code that removes the byte from the output queue, so one byte would
be lost every time the hardware FIFO is full.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/oss/midibuf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/sound/oss/midibuf.c b/sound/oss/midibuf.c
index a40be0cf1d9..782b3b84dac 100644
--- a/sound/oss/midibuf.c
+++ b/sound/oss/midibuf.c
@@ -127,15 +127,16 @@ static void midi_poll(unsigned long dummy)
 		for (dev = 0; dev < num_midis; dev++)
 			if (midi_devs[dev] != NULL && midi_out_buf[dev] != NULL)
 			{
-				int ok = 1;
-
-				while (DATA_AVAIL(midi_out_buf[dev]) && ok)
+				while (DATA_AVAIL(midi_out_buf[dev]))
 				{
+					int ok;
 					int c = midi_out_buf[dev]->queue[midi_out_buf[dev]->head];
 
 					spin_unlock_irqrestore(&lock,flags);/* Give some time to others */
 					ok = midi_devs[dev]->outputc(dev, c);
 					spin_lock_irqsave(&lock, flags);
+					if (!ok)
+						break;
 					midi_out_buf[dev]->head = (midi_out_buf[dev]->head + 1) % MAX_QUEUE_SIZE;
 					midi_out_buf[dev]->len--;
 				}
-- 
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