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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Jerome Brunet <jbrunet@baylibre.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>, alsa-devel@alsa-project.org
Subject: [PATCH AUTOSEL 5.6 45/79] ASoC: meson: axg-card: fix codec-to-codec link setup
Date:   Thu, 30 Apr 2020 09:50:09 -0400
Message-Id: <20200430135043.19851-45-sashal@kernel.org>
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From: Jerome Brunet <jbrunet@baylibre.com>

[ Upstream commit 1164284270779e1865cc2046a2a01b58a1e858a9 ]

Since the addition of commit 9b5db059366a ("ASoC: soc-pcm: dpcm: Only allow
playback/capture if supported"), meson-axg cards which have codec-to-codec
links fail to init and Oops:

  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000128
  Internal error: Oops: 96000044 [#1] PREEMPT SMP
  CPU: 3 PID: 1582 Comm: arecord Not tainted 5.7.0-rc1
  pc : invalidate_paths_ep+0x30/0xe0
  lr : snd_soc_dapm_dai_get_connected_widgets+0x170/0x1a8
  Call trace:
   invalidate_paths_ep+0x30/0xe0
   snd_soc_dapm_dai_get_connected_widgets+0x170/0x1a8
   dpcm_path_get+0x38/0xd0
   dpcm_fe_dai_open+0x70/0x920
   snd_pcm_open_substream+0x564/0x840
   snd_pcm_open+0xfc/0x228
   snd_pcm_capture_open+0x4c/0x78
   snd_open+0xac/0x1a8
   ...

While initiliazing the links, ASoC treats the codec-to-codec links of this
card type as a DPCM backend. This error eventually leads to the Oops.

Most of the card driver code is shared between DPCM backends and
codec-to-codec links. The property "no_pcm" marking DCPM BE was left set on
codec-to-codec links, leading to this problem. This commit fixes that.

Fixes: 0a8f1117a680 ("ASoC: meson: axg-card: add basic codec-to-codec link support")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200420114511.450560-2-jbrunet@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/soc/meson/axg-card.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/soc/meson/axg-card.c b/sound/soc/meson/axg-card.c
index 1f698adde506c..2b04ac3d8fd3b 100644
--- a/sound/soc/meson/axg-card.c
+++ b/sound/soc/meson/axg-card.c
@@ -586,8 +586,10 @@ static int axg_card_add_link(struct snd_soc_card *card, struct device_node *np,
 
 	if (axg_card_cpu_is_tdm_iface(dai_link->cpus->of_node))
 		ret = axg_card_parse_tdm(card, np, index);
-	else if (axg_card_cpu_is_codec(dai_link->cpus->of_node))
+	else if (axg_card_cpu_is_codec(dai_link->cpus->of_node)) {
 		dai_link->params = &codec_params;
+		dai_link->no_pcm = 0; /* link is not a DPCM BE */
+	}
 
 	return ret;
 }
-- 
2.20.1