Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e999dc50 authored by Mark Brown's avatar Mark Brown
Browse files

ASoC: Fix Blackfin I2S _pointer() implementation return in bounds values 



The Blackfin DMA controller can report one frame beyond the end of the
buffer in the wraparound case but ALSA requires that the pointer always
be in the buffer. Do the wraparound to handle this. A similar bug is
likely to apply to the other Blackfin PCM drivers but the code is less
obvious to inspection and I don't have a user to test.

Reported-by: default avatarKieran O'Leary <Kieran.O'Leary@wolfsonmicro.com>
Acked-by: default avatarLiam Girdwood <lrg@ti.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org
parent 53dea36c

sound/soc/blackfin/bf5xx-i2s-pcm.c

+11 −2
Original line number Diff line number Diff line
@@ -138,11 +138,20 @@ static snd_pcm_uframes_t bf5xx_pcm_pointer(struct snd_pcm_substream *substream) 
	pr_debug("%s enter\n", __func__);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

		diff = sport_curr_offset_tx(sport);

		frames = bytes_to_frames(substream->runtime, diff);

	} else {

		diff = sport_curr_offset_rx(sport);

		frames = bytes_to_frames(substream->runtime, diff);

	}



	/*

	 * TX at least can report one frame beyond the end of the

	 * buffer if we hit the wraparound case - clamp to within the

	 * buffer as the ALSA APIs require.

	 */

	if (diff == snd_pcm_lib_buffer_bytes(substream))

		diff = 0;



	frames = bytes_to_frames(substream->runtime, diff);



	return frames;

}