linux-kernel - [PATCH AUTOSEL 3.18 2/8] ASoC:soc-pcm:fix a codec fixup issue in TDM case

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Message-Id: <20190427014412.9091-2-sashal@kernel.org>
Date:   Fri, 26 Apr 2019 21:44:05 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Rander Wang <rander.wang@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 3.18 2/8] ASoC:soc-pcm:fix a codec fixup issue in TDM case

From: Rander Wang <rander.wang@...ux.intel.com>

[ Upstream commit 570f18b6a8d1f0e60e8caf30e66161b6438dcc91 ]

On HDaudio platforms, if playback is started when capture is working,
there is no audible output.

This can be root-caused to the use of the rx|tx_mask to store an HDaudio
stream tag.

If capture is stared before playback, rx_mask would be non-zero on HDaudio
platform, then the channel number of playback, which is in the same codec
dai with the capture, would be changed by soc_pcm_codec_params_fixup based
on the tx_mask at first, then overwritten by this function based on rx_mask
at last.

According to the author of tx|rx_mask, tx_mask is for playback and rx_mask
is for capture. And stream direction is checked at all other references of
tx|rx_mask in ASoC, so here should be an error. This patch checks stream
direction for tx|rx_mask for fixup function.

This issue would affect not only HDaudio+ASoC, but also I2S codecs if the
channel number based on rx_mask is not equal to the one for tx_mask. It could
be rarely reproduecd because most drivers in kernel set the same channel number
to tx|rx_mask or rx_mask is zero.

Tested on all platforms using stream_tag & HDaudio and intel I2S platforms.

Signed-off-by: Rander Wang <rander.wang@...ux.intel.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/soc-pcm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index e2fb859fbbaa..4323002c67db 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -847,10 +847,13 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
 		codec_params = *params;

 		/* fixup params based on TDM slot masks */
-		if (codec_dai->tx_mask)
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+		    codec_dai->tx_mask)
 			soc_pcm_codec_params_fixup(&codec_params,
 						   codec_dai->tx_mask);
-		if (codec_dai->rx_mask)
+
+		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE &&
+		    codec_dai->rx_mask)
 			soc_pcm_codec_params_fixup(&codec_params,
 						   codec_dai->rx_mask);

-- 
2.19.1