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>

diff --git a/sound/oss/midibuf.c b/sound/oss/midibuf.c
index a40be0cf1d97f42bf6a180312afbc10b15c7a5bc..782b3b84dac68ccd036c52ee3533336f243ac15b 100644 (file)
--- 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--;
                                }