Those are (part of) the errors I get when starting VLC from terminal to watch dvb:
[msmpeg4 @ 0x7f8774c4d500] get_buffer() failed
[msmpeg4 @ 0x7f8774c4d500] get_buffer() failed (-12 (nil))
[00007f8778327110] mpeg4audio packetizer: AAC channels: 2 samplerate: 48000
[00007f877802ec80] main decoder error: buffer deadlock prevented
[00007f8764020e70] gl gl: Initialized libplacebo v4.208.0 (API v208)
libva info: VA-API version 1.18.0
libva error: vaGetDriverNameByIndex() failed with unknown libva error, driver_name = (null)
[00007f8764020e70] glconv_vaapi_x11 gl error: vaInitialize: unknown libva error
libva info: VA-API version 1.18.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/nvidia_drv_video.so
libva info: va_openDriver() returns -1
[00007f8764020e70] glconv_vaapi_drm gl error: vaInitialize: unknown libva error
libva info: VA-API version 1.18.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/nvidia_drv_video.so
libva info: va_openDriver() returns -1
[00007f8764020e70] glconv_vaapi_drm gl error: vaInitialize: unknown libva error
[00007f8764020e70] gl gl: Initialized libplacebo v4.208.0 (API v208)
[00007f877802ec80] avcodec decoder: Using NVIDIA VDPAU Driver Shared Library 470.182.03 Fri Feb 24 03:16:35 UTC 2023 for hardware decoding
[hevc @ 0x7f876c008740] Failed setup for format vdpau: hwaccel initialisation returned error.
[00007f877802ec80] avcodec decoder error: existing hardware acceleration cannot be reused
[00007f8764020e70] gl gl: Initialized libplacebo v4.208.0 (API v208)
[00007f8764020e70] gl gl: Initialized libplacebo v4.208.0 (API v208)
[hevc @ 0x7f876c03c400] get_buffer() failed
[hevc @ 0x7f876c03c400] thread_get_buffer() failed
In this case I can close VLC after closing the xterm I used to open it.
The VLC problem seems related to dvb because I can watch local videos and VLC still remains responsive. However, when I open a dvb connection the first broadcast station on the list will play. Trying to change the station will freeze the GUI.
So using it as a music player won't lead to the failure, I assume.
No such problems with kernel 6.3.7 or prior.
Edit:
New (todays) siduction kernel 6.3.8 has the same problem.
New (todays) pure Debian Kernel 6.3.0 has the same Problem.
Last working with siduction 6.3.7 and Debian 6.1.0.
For the record, all mentioned Kernel have siduction/towo patched nvidia driver, working ones and not working ones. The Debian Kernel do not compile without the nvidia patches!
One more thing: the hang is so deep in the systen that systemd-shutdown service hangs endlessly. I have to hardresett the system.
Given all those observations I assume the failiure is not siduction specific but Debian or Kernel.org specific. Will file a bugreport against Debian 6.3.0 . For now closed here.