alsa-project/alsa-python issue #13 was edited from tormodvolden:
Version 1.2.12, on Ubuntu 24.04, Python 3.12.
It seems like the "status" member returned by `snd_ctl_elem_value_get_iec958(self->value, iec958);` on pyalsa/alsahcontrol.c line 1053 starts with 0xff then a 0x00.
I haven't been able to find a corresponding node under /proc/asound to check this.
The relevant aplay -L entry is ``` iec958:CARD=Stereo,DEV=0 Logitech H570e Stereo, USB Audio IEC958 (S/PDIF) Digital Audio Output ``` Here is a dump of /proc/asound/card1 (card 1 is called "Stereo") <details>
``` $ more $(find /proc/asound/card1 -type f) :::::::::::::: /proc/asound/card1/id :::::::::::::: Stereo :::::::::::::: /proc/asound/card1/pcm0c/info :::::::::::::: card: 1 device: 0 subdevice: 0 stream: CAPTURE id: USB Audio name: USB Audio subname: subdevice #0 class: 0 subclass: 0 subdevices_count: 1 subdevices_avail: 1 :::::::::::::: /proc/asound/card1/pcm0c/sub0/info :::::::::::::: card: 1 device: 0 subdevice: 0 stream: CAPTURE id: USB Audio name: USB Audio subname: subdevice #0 class: 0 subclass: 0 subdevices_count: 1 subdevices_avail: 1 :::::::::::::: /proc/asound/card1/pcm0c/sub0/status :::::::::::::: closed :::::::::::::: /proc/asound/card1/pcm0c/sub0/hw_params :::::::::::::: closed :::::::::::::: /proc/asound/card1/pcm0c/sub0/sw_params :::::::::::::: closed :::::::::::::: /proc/asound/card1/pcm0p/info :::::::::::::: card: 1 device: 0 subdevice: 0 stream: PLAYBACK id: USB Audio name: USB Audio subname: subdevice #0 class: 0 subclass: 0 subdevices_count: 1 subdevices_avail: 0 :::::::::::::: /proc/asound/card1/pcm0p/sub0/info :::::::::::::: card: 1 device: 0 subdevice: 0 stream: PLAYBACK id: USB Audio name: USB Audio subname: subdevice #0 class: 0 subclass: 0 subdevices_count: 1 subdevices_avail: 0 :::::::::::::: /proc/asound/card1/pcm0p/sub0/status :::::::::::::: state: RUNNING owner_pid : 1928 trigger_time: 270044.979966617 tstamp : 309371.219688371 delay : 1872 avail : 31520 avail_max : 32032 ----- hw_ptr : 1887652896 appl_ptr : 1887654144 :::::::::::::: /proc/asound/card1/pcm0p/sub0/hw_params :::::::::::::: access: MMAP_INTERLEAVED format: S16_LE subformat: STD channels: 2 rate: 48000 (48000/1) period_size: 256 buffer_size: 32768 :::::::::::::: /proc/asound/card1/pcm0p/sub0/sw_params :::::::::::::: tstamp_mode: ENABLE period_step: 1 avail_min: 256 start_threshold: 9223372036854775807 stop_threshold: 32768 silence_threshold: 0 silence_size: 0 boundary: 4611686018427387904 :::::::::::::: /proc/asound/card1/usbid :::::::::::::: 046d:0a56 :::::::::::::: /proc/asound/card1/usbbus :::::::::::::: 003/006 :::::::::::::: /proc/asound/card1/stream0 :::::::::::::: Logitech Inc Logitech H570e Stereo at usb-0000:00:14.0-4.4.2, full speed : USB A udio
Playback: Status: Running Interface = 2 Altset = 1 Packet Size = 192 Momentary freq = 48000 Hz (0x30.0000) Interface 2 Altset 1 Format: S16_LE Channels: 2 Endpoint: 0x01 (1 OUT) (ADAPTIVE) Rates: 8000, 16000, 24000, 32000, 44100, 48000 Bits: 16 Channel map: FL FR
Capture: Status: Stop Interface 1 Altset 1 Format: S16_LE Channels: 2 Endpoint: 0x81 (1 IN) (ASYNC) Rates: 8000, 16000, 24000, 32000, 44100, 48000 Bits: 16 Channel map: FL FR :::::::::::::: /proc/asound/card1/usbmixer :::::::::::::: USB Mixer: usb_id=0x046d0a56, ctrlif=0, ctlerr=0 Card: Logitech Inc Logitech H570e Stereo at usb-0000:00:14.0-4.4.2, full speed Unit: 2 Control: name="Auto Gain Control", index=0 Info: id=2, control=7, cmask=0x0, channels=1, type="BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 2 Control: name="Headset Capture Volume", index=0 Info: id=2, control=2, cmask=0x0, channels=1, type="S16" Volume: min=-7680, max=1280, dBmin=-3000, dBmax=500 Unit: 2 Control: name="Headset Capture Switch", index=0 Info: id=2, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 5 Control: name="Headset Playback Volume", index=0 Info: id=5, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-15360, max=1280, dBmin=-6000, dBmax=500 Unit: 5 Control: name="Headset Playback Switch", index=0 Info: id=5, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 11 Control: name="Sidetone Playback Volume", index=0 Info: id=11, control=2, cmask=0x0, channels=1, type="S16" Volume: min=0, max=4125, dBmin=0, dBmax=1611 Unit: 11 Control: name="Sidetone Playback Switch", index=0 Info: id=11, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 ``` </details>
This is the last part of the output from running `python3 test/hctltest1.py ` ``` ***** count: 1 device: 0 dimensions: None element: <alsahcontrol.Element object at 0x7e418ebb9650> id: (19, 2, 0, 0, 'IEC958 Playback Con Mask', 0) index: 0 interface: 2 is_inactive: False is_locked: False is_owner: False is_readable: True is_tlv_Commandable: False is_tlv_Writable: False is_tlv_readable: False is_user: False is_volatile: False is_writable: False name: IEC958 Playback Con Mask numid: 19 owner: -1 subdevice: 0 type: 5 (IEC958) ----- device: 0 element: <alsahcontrol.Element object at 0x7e418ebb9650> get_array: <built-in method get_array of alsahcontrol.Value object at 0x7e418ebb9620> get_tuple: <built-in method get_tuple of alsahcontrol.Value object at 0x7e418ebb9620> id: (19, 2, 0, 0, 'IEC958 Playback Con Mask', 0) index: 0 interface: 2 name: IEC958 Playback Con Mask numid: 19 read: <built-in method read of alsahcontrol.Value object at 0x7e418ebb9620> set_array: <built-in method set_array of alsahcontrol.Value object at 0x7e418ebb9620> set_tuple: <built-in method set_tuple of alsahcontrol.Value object at 0x7e418ebb9620> subdevice: 0 write: <built-in method write of alsahcontrol.Value object at 0x7e418ebb9620> UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 1: invalid start byte
The above exception was the direct cause of the following exception:
Traceback (most recent call last): File "/home/tormod/SOURCES/pyalsa-debian/python-pyalsa/test/hctltest1.py", line 69, in <module> value(element1) File "/home/tormod/SOURCES/pyalsa-debian/python-pyalsa/test/hctltest1.py", line 36, in value values = value.get_tuple(info.type, info.count) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SystemError: <method 'get_tuple' of 'alsahcontrol.Value' objects> returned a result with an exception set ```
info.type is 5 info.count is 1
Issue URL : https://github.com/alsa-project/alsa-python/issues/13 Repository URL: https://github.com/alsa-project/alsa-python