From mboxrd@z Thu Jan  1 00:00:00 1970
From: Timur Tabi <timur@freescale.com>
Subject: Re: How does ALSA detect underrun in OSS emulation?
Date: Mon, 25 Feb 2008 09:38:38 -0600
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References: <47C2DD41.9070408@freescale.com> <s5hhcfxt5ih.wl%tiwai@suse.de>
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To: Takashi Iwai <tiwai@suse.de>
Cc: alsa-devel@alsa-project.org
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Takashi Iwai wrote:

> It's just as same as on ALSA native API, checks the validity of the
> current position reported by pointer callback in
> snd_pcm_period_elapsed().

Are you talking about this code in snd_pcm_update_hw_ptr_pos?

	pos = substream->ops->pointer(substream);
	if (pos == SNDRV_PCM_POS_XRUN)
		return pos; /* XRUN */

What if my 'pointer' function never returns SNDRV_PCM_POS_XRUN?  How else can I 
get an underrun detected?

-- 
Timur Tabi
Linux kernel developer at Freescale