[Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal

[Jan Kiszka <jan.kiszka@web.de>]

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malc wrote:
> So just leave the callback until free get's big enough, you will get
> dropouts either way, it's just that. I guess you might also use the
> AUD_init_time_stamp_out/AUD_get_elapsed_usec_out mechanism (implemenation
> is right at the end of audio/audio_template.h), but i still think that
> just going with free is saner approach.

Well, took some iterations to switch my mind completely to the new
model, but now this timestamp-free version runs as smooth as the
previous one:

static void audio_callback(void *opaque, int free)
{
	mv88w8618_audio_state *s = opaque;
	unsigned int block_size, written;

	block_size = s->threshold/2 - s->block_written;
	if (free - s->last_free < block_size)
		return;

	audio_fill_mixer_buffer(s, block_size);
	written = AUD_write(s->voice, s->mixer_buffer, block_size);

	s->last_free = free - written;

	if (written < block_size) {
		s->block_written += written;
		return;
	}
	s->block_written = 0;

	if (s->play_pos == 0) {
		s->status |= MP_AUDIO_TX_HALF;
		s->play_pos = s->threshold/2;
	} else {
		s->status |= MP_AUDIO_TX_FULL;
		s->play_pos = 0;
	}

	if (s->status & s->irq_enable)
		qemu_irq_raise(s->irq);
}

[ This would be even simpler if I could assume written == block_size ||
  written == 0. But who knows... ]

Jan


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