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Commit ded652f7 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: pcm - Fix delta calculation at boundary overlap 



When the hw_ptr_interrupt reaches the boundary, it must check whether
the hw_base was already lapped and corret the delta value appropriately.

Also, rebasing the hw_ptr needs a correction because buffer_size isn't
always aligned to period_size.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 5f513e11

sound/core/pcm_lib.c

+7 −2
Original line number Diff line number Diff line
@@ -221,8 +221,11 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream) 
	new_hw_ptr = hw_base + pos;

	hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;

	delta = new_hw_ptr - hw_ptr_interrupt;

	if (hw_ptr_interrupt == runtime->boundary)

		hw_ptr_interrupt = 0;

	if (hw_ptr_interrupt >= runtime->boundary) {

		hw_ptr_interrupt %= runtime->boundary;

		if (!hw_base) /* hw_base was already lapped; recalc delta */

			delta = new_hw_ptr - hw_ptr_interrupt;

	}

	if (delta < 0) {

		delta += runtime->buffer_size;

		if (delta < 0) {
@@ -233,6 +236,8 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream) 
				     (long)hw_ptr_interrupt);

			/* rebase to interrupt position */

			hw_base = new_hw_ptr = hw_ptr_interrupt;

			/* align hw_base to buffer_size */

			hw_base -= hw_base % runtime->buffer_size;

			delta = 0;

		} else {

			hw_base += runtime->buffer_size;