@@ -2911,8 +2911,17 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
int i;
if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) {
- playback = rtd->dai_link->dpcm_playback;
- capture = rtd->dai_link->dpcm_capture;
+ cpu_dai = asoc_rtd_to_cpu(rtd, 0);
+ if (rtd->num_cpus > 1) {
+ dev_err(rtd->dev,
+ "DPCM doesn't support Multi CPU yet\n");
+ return -EINVAL;
+ }
+
+ playback = rtd->dai_link->dpcm_playback &&
+ snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_PLAYBACK);
+ capture = rtd->dai_link->dpcm_capture &&
+ snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_CAPTURE);
} else {
/* Adapt stream for codec2codec links */
int cpu_capture = rtd->dai_link->params ?
At the moment, PCM devices for DPCM are only created based on the dpcm_playback/capture parameters of the DAI link, without considering if the CPU/FE DAI is actually capable of playback/capture. Normally the dpcm_playback/capture parameter should match the capabilities of the CPU DAI. However, there is no way to set that parameter from the device tree (e.g. with simple-audio-card or qcom sound cards). dpcm_playback/capture are always both set to 1. This causes problems when the CPU DAI does only support playback or capture. Attemting to open that PCM device with an unsupported stream type then results in a null pointer dereference: 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 ... ... because the DAI playback/capture_widget is not set in that case. We could add checks there to fix the problem (maybe we should anyway), but much easier is to not expose the device as playback/capture in the first place. Attemting to use that device would always fail later anyway. Add checks for snd_soc_dai_stream_valid() to the DPCM case to avoid exposing playback/capture if it is not supported. Signed-off-by: Stephan Gerhold <stephan@gerhold.net> --- This can be reproduced with q6asm-dai with a device tree configuration like: &q6asmdai { dai@0 { reg = <0>; direction = <Q6ASM_DAI_RX>; }; }; Then a simple "arecord output.wav" will result in the crash above, since it attempts to use that FE DAI for capture (even though it is limited to playback). --- sound/soc/soc-pcm.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)