sound: fix OSS MIDI output data loss (5e8e7c38) · Commits · 戴 / test

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

+4 −3

Original line number	Diff line number	Diff line
		@@ -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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