[alsa-devel] [PATCH] ASoC: pxa: remove duplicated snd_soc_component_driver ops

[petrcvekcz at gmail.com]

From: Petr Cvek <petrcvekcz at gmail.com>

The sound soc drivers which are using a platform driver pxa-pcm-audio and
cpu dai drivers from the pxa tree have defined pxa2xx_soc_pcm_new() twice.
The function will get called in soc_new_pcm() for two components (platform
and cpu dai) which causes a double allocation of DMA resources and later
during a close of the playback/capture a kernel warning:

 WARNING: CPU: 0 PID: 892 at drivers/dma/dmaengine.c:788 dma_release_channel+0x44/0xa0
 chan reference count 0 != 1
 Modules linked in: snd_soc_magician snd_soc_pxa2xx snd_pxa2xx_lib ...
 CPU: 0 PID: 892 Comm: aplay Tainted: G C 4.18.0-rc6-next-20180726-magician+ #16
 Hardware name: HTC Magician
 [<c0107d90>] (unwind_backtrace) from [<c010594c>] (show_stack+0x10/0x14)
 [<c010594c>] (show_stack) from [<c0111680>] (__warn+0xd4/0xec)
 [<c0111680>] (__warn) from [<c01112d0>] (warn_slowpath_fmt+0x44/0x6c)
 [<c01112d0>] (warn_slowpath_fmt) from [<c034908c>] (dma_release_channel+0x44/0xa0)
 [<c034908c>] (dma_release_channel) from [<bf330528>] (snd_dmaengine_pcm_close_release_chan+0x44/0xb1c [snd_pcm_dmaengine])
 [<bf330528>] (snd_dmaengine_pcm_close_release_chan [snd_pcm_dmaengine]) from [<bf26c29c>] (soc_pcm_components_close+0x8c/0xac [snd_soc_core])
 [<bf26c29c>] (soc_pcm_components_close [snd_soc_core]) from [<bf26c3a0>] (soc_pcm_close+0xe4/0xd44 [snd_soc_core])
 [<bf26c3a0>] (soc_pcm_close [snd_soc_core]) from [<bf167254>] (snd_pcm_release_substream+0x88/0x108 [snd_pcm])
 [<bf167254>] (snd_pcm_release_substream [snd_pcm]) from [<bf167330>] (snd_pcm_release+0x5c/0xd2c [snd_pcm])
 [<bf167330>] (snd_pcm_release [snd_pcm]) from [<c01c39e4>] (__fput+0xdc/0x1e8)
 [<c01c39e4>] (__fput) from [<c0129e7c>] (task_work_run+0xc4/0xd4)
 [<c0129e7c>] (task_work_run) from [<c01053ac>] (do_work_pending+0xc0/0xc8)
 [<c01053ac>] (do_work_pending) from [<c0101068>] (slow_work_pending+0xc/0x20)
 Exception stack(0xc2fdffb0 to 0xc2fdfff8)
 ffa0:                                     00000000 0154d1a0 01542a3c 00000000
 ffc0: 0154d150 00000000 0009283c 00000006 000003f0 0154d4c8 00000000 0154d4c8
 ffe0: b6ee7d70 bef13960 b6e547b8 b6cfe018 60000010 00000004

The problem was found for cpu dai drivers: pxa-i2s and pxa-ssp and by
a calltrace sent from Robert Jarzmik on pxa-ac97 (although there was no
observed kernel warning). The git grep shows these 3 cpu dai drivers are
the only one which assign the .pcm_new to pxa2xx_soc_pcm_new() and almost
every machine which is using one of these cpu dai drivers is using the
platform driver pxa-pcm-audio too. The only exception is TTC_DKB board
which is using a platform driver mmp-pcm-audio. A quick look in the code
of mmp-pcm-audio shows it allocates the DMA in the similar way as PXA.

The solution is to remove one of pxa2xx_soc_pcm_new() assignments and the
patch does it for 3 cpu dai drivers (SSP/I2S/AC97).

The result was tested on HTC Magician board (SSP for playback, I2S for
capture) and the DMA buffers are correctly allocated.

Signed-off-by: Petr Cvek <petrcvekcz at gmail.com>
---
 sound/soc/pxa/pxa-ssp.c     | 3 ---
 sound/soc/pxa/pxa2xx-ac97.c | 3 ---
 sound/soc/pxa/pxa2xx-i2s.c  | 3 ---
 3 files changed, 9 deletions(-)

diff --git a/sound/soc/pxa/pxa-ssp.c b/sound/soc/pxa/pxa-ssp.c
index 69033e1a84e6..9689a1552d53 100644
--- a/sound/soc/pxa/pxa-ssp.c
+++ b/sound/soc/pxa/pxa-ssp.c
@@ -867,9 +867,6 @@ static struct snd_soc_dai_driver pxa_ssp_dai = {
 
 static const struct snd_soc_component_driver pxa_ssp_component = {
 	.name		= "pxa-ssp",
-	.ops		= &pxa2xx_pcm_ops,
-	.pcm_new	= pxa2xx_soc_pcm_new,
-	.pcm_free	= pxa2xx_pcm_free_dma_buffers,
 };
 
 #ifdef CONFIG_OF
diff --git a/sound/soc/pxa/pxa2xx-ac97.c b/sound/soc/pxa/pxa2xx-ac97.c
index 9f779657bc86..c52b33802bf2 100644
--- a/sound/soc/pxa/pxa2xx-ac97.c
+++ b/sound/soc/pxa/pxa2xx-ac97.c
@@ -214,9 +214,6 @@ static struct snd_soc_dai_driver pxa_ac97_dai_driver[] = {
 
 static const struct snd_soc_component_driver pxa_ac97_component = {
 	.name		= "pxa-ac97",
-	.ops		= &pxa2xx_pcm_ops,
-	.pcm_new	= pxa2xx_soc_pcm_new,
-	.pcm_free	= pxa2xx_pcm_free_dma_buffers,
 };
 
 #ifdef CONFIG_OF
diff --git a/sound/soc/pxa/pxa2xx-i2s.c b/sound/soc/pxa/pxa2xx-i2s.c
index 42820121e5b9..e7184de0de04 100644
--- a/sound/soc/pxa/pxa2xx-i2s.c
+++ b/sound/soc/pxa/pxa2xx-i2s.c
@@ -364,9 +364,6 @@ static struct snd_soc_dai_driver pxa_i2s_dai = {
 
 static const struct snd_soc_component_driver pxa_i2s_component = {
 	.name		= "pxa-i2s",
-	.ops		= &pxa2xx_pcm_ops,
-	.pcm_new	= pxa2xx_soc_pcm_new,
-	.pcm_free	= pxa2xx_pcm_free_dma_buffers,
 };
 
 static int pxa2xx_i2s_drv_probe(struct platform_device *pdev)
-- 
2.18.0