alsa-project/alsa-lib issue #354 was opened from leezu:

Dear Alsa developers,

for [Asurada Spherion](https://www.acer.com/us-en/chromebooks/acer-chromebook-514-cb514-2h-cb514-2h...), https://github.com/torvalds/linux/commit/ad5cc915c300d4ea733da80ae714fdad378... enabled audio support for this hardware in the kernel. https://github.com/alsa-project/alsa-ucm-conf/commit/2667378a6b9120d99e44f78... added the associated UCM files. Nevertheless, audio does not work even with latest alsa 1.2.10 and linux 6.5.4.

UCM does seem to recognize the device correctly:

<details><summary>ucm output</summary>

``` alsaucm listcards 0: hw:0 mt8192_mt6359_rt1015p_rt5682

alsaucm dump text Verb.HiFi { Comment Default Device.Speaker { Comment Speaker Values { CaptureCTL "_ucm0001.hw:mt8192mt6359rt1" PlaybackCTL "_ucm0001.hw:mt8192mt6359rt1" PlaybackPCM "_ucm0001.hw:mt8192mt6359rt1,0" PlaybackPriority 100 TQ HiFi } } Device.Headphones { Comment Headphones Values { CaptureCTL "_ucm0001.hw:mt8192mt6359rt1" JackControl "Headphone Jack" PlaybackCTL "_ucm0001.hw:mt8192mt6359rt1" PlaybackMixerElem DAC1 PlaybackPCM "_ucm0001.hw:mt8192mt6359rt1,3" PlaybackPriority 200 TQ HiFi } } Device.Mic { Comment "Internal Microphone" Values { CaptureCTL "_ucm0001.hw:mt8192mt6359rt1" CapturePCM "_ucm0001.hw:mt8192mt6359rt1,10" CapturePriority 100 PlaybackCTL "_ucm0001.hw:mt8192mt6359rt1" TQ HiFi } } Device.Headset { Comment "Headset Microphone" Values { CaptureCTL "_ucm0001.hw:mt8192mt6359rt1" CapturePCM "_ucm0001.hw:mt8192mt6359rt1,11" CapturePriority 200 JackControl "Headset Mic Jack" PlaybackCTL "_ucm0001.hw:mt8192mt6359rt1" TQ HiFi } } } ```

</details>

Enabling pulseaudio or wireplumber for audio support yields a dysfunctional system, for example causing any application trying to play audio to hang when wireplumber is enabled. Thus, I tried debugging the issue using lower-level alsa tools, such as aplay. Running aplay fails with `unable to install hw params`:

<details><summary>aplay output</summary>

``` aplay /usr/share/sounds/alsa/Front_Center.wav --verbose --dump-hw-params -D hw:0 Playing WAVE '/usr/share/sounds/alsa/Front_Center.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono HW Params of device "hw:0": -------------------- ACCESS: MMAP_INTERLEAVED RW_INTERLEAVED FORMAT: S16_LE S24_LE S32_LE SUBFORMAT: STD SAMPLE_BITS: [16 32] FRAME_BITS: [16 64] CHANNELS: [1 2] RATE: [8000 192000] PERIOD_TIME: (62 6144000] PERIOD_SIZE: [12 49152] PERIOD_BYTES: [96 196608] PERIODS: [2 256] BUFFER_TIME: [125 12288000] BUFFER_SIZE: [24 98304] BUFFER_BYTES: [96 196608] TICK_TIME: ALL -------------------- aplay: set_params:1435: Unable to install hw params: ACCESS: RW_INTERLEAVED FORMAT: S16_LE SUBFORMAT: STD SAMPLE_BITS: 16 FRAME_BITS: 16 CHANNELS: 1 RATE: 48000 PERIOD_TIME: 125000 PERIOD_SIZE: 6000 PERIOD_BYTES: 12000 PERIODS: 4 BUFFER_TIME: 500000 BUFFER_SIZE: 24000 BUFFER_BYTES: 48000 TICK_TIME: 0

```

</details>

Using gdb to debug aplay shows that alsa fails in snd_pcm_hw_prepare when calling ioctl(fd, SNDRV_PCM_IOCTL_PREPARE), due to EINVAL, indicating that the request or argp argument is not valid.

<details><summary>gdb output</summary> <p>

``` $ gdb aplay GNU gdb (Debian 13.1-3) 13.1 Copyright (C) 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "aarch64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: https://www.gnu.org/software/gdb/bugs/. Find the GDB manual and other documentation resources online at: http://www.gnu.org/software/gdb/documentation/.

For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from aplay... Reading symbols from /usr/lib/debug/.build-id/fd/47982108e1aa7250d338ed6e26020eeaeee782.debug... (gdb) break snd_pcm_hw_prepare Function "snd_pcm_hw_prepare" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 1 (snd_pcm_hw_prepare) pending. (gdb) directory /dev/shm/alsa-lib-1.2.10 Source directories searched: /dev/shm/alsa-lib-1.2.10:$cdir:$cwd (gdb) run /usr/share/sounds/alsa/Front_Center.wav --verbose --dump-hw-params -D hw:0 Starting program: /usr/bin/aplay /usr/share/sounds/alsa/Front_Center.wav --verbose --dump-hw-params -D hw:0 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1". Playing WAVE '/usr/share/sounds/alsa/Front_Center.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono HW Params of device "hw:0": -------------------- ACCESS: MMAP_INTERLEAVED RW_INTERLEAVED FORMAT: S16_LE S24_LE S32_LE SUBFORMAT: STD SAMPLE_BITS: [16 32] FRAME_BITS: [16 64] CHANNELS: [1 2] RATE: [8000 192000] PERIOD_TIME: (62 6144000] PERIOD_SIZE: [12 49152] PERIOD_BYTES: [96 196608] PERIODS: [2 256] BUFFER_TIME: [125 12288000] BUFFER_SIZE: [24 98304] BUFFER_BYTES: [96 196608] TICK_TIME: ALL --------------------

Breakpoint 1, snd_pcm_hw_prepare (pcm=0xaaaaaaafd860) at ./src/pcm/pcm_hw.c:668 668 { (gdb) n 673 if (hw->prepare_reset_sw_params) { (gdb) n 682 if (ioctl(fd, SNDRV_PCM_IOCTL_PREPARE) < 0) { (gdb) n 683 err = -errno; (gdb) n 684 SYSMSG("SNDRV_PCM_IOCTL_PREPARE failed (%i)", err); (gdb) p err $1 = -22

```

</p> </details>

It is quite possible that there is a kernel bug causing this issue. It would be very helpful if you can advise how to continue debugging this issue, as I'm not sufficiently familiar with the alsa stack. I'm happy to provide additional information. Please let me know what could be helpful.

Issue URL : https://github.com/alsa-project/alsa-lib/issues/354 Repository URL: https://github.com/alsa-project/alsa-lib