From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Young <Alan.Young@IEE.org>
Subject: Difference between boundary and buffer_size
Date: Thu, 3 Nov 2016 09:11:04 +0000
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The code in the kernel, in /pcm_lib.c/ and /pcm_native.c/, uses fields 
buffer_size and boundary in struct snd_pcm_runtime. As far as I can see, 
there are always initialized to the same value. In what circumstance 
might they be different? There is clearly some relationship to 
hw_ptr_base, as illustrated by this repeated snipped from 
snd_pcm_update_hw_ptr0()

		hw_base += runtime->buffer_size;
		if (hw_base >= runtime->boundary) {
			hw_base = 0;
			crossed_boundary++;
		}
		new_hw_ptr = hw_base + pos;

Alan.