XPost: aus.computers   
   From: none@not.here   
      
   Paul wrote:   
   > On Sun, 8/10/2025 8:23 PM, Felix wrote:   
   >> I upgraded a linux box from LM 22 to LM 22.1 via software manager when   
   prompted, but now have no sound, because HDMI does not appear in sound manager   
   as an output option, only SPDIF. I have tried changing drivers. How to fix   
   please?   
   >>   
   >>   
      
   Hi Paul   
      
   >     [Picture]   
   >   
   >      https://i.postimg.cc/3xbJ7gyz/LM221-soundworks-HDMI.png   
   >   
   > The sound driver on three audio devices in INXI, is "snd_hda_intel",   
   > because some controller in there, looks like a bus host for   
   > HDAudio serial bus.   
   >   
   > Video cards first had no sound. HDMI existed and worked, but   
   > no 8ch LPCM (linear pulse code modulation) was available. The HDMI standard   
   > defined how the audio samples were to be multiplexed in, but the cards   
   > didn't have the logic block for it at the time.   
   >   
   > The first HDMI "experiment", was to place a 2-channel SPDIF TTL-level signal   
   on   
   > a connector on the top edge of the video card. This should not require a   
   driver,   
   > as the SPDIF was just multiplexed into HDMI right from the connector   
   > (with suitable rate adaptation). A number of motherboards, had an SPDIF   
   connector   
   > coming from the motherboard audio chip, but not a lot of users had the balls   
   to   
   > connect that signal to their (expensive) video card and risk blowing it. And   
   there   
   > was no documentation (as usual), defining the electrical characteristic on   
   > either end. It's just my *guess*, it was a TTL or 3.3V CMOS type logic   
   signal,   
   > with not a lot of drive capability (less than 8mA drive).   
   >   
   > But this isn't particular "standards based". NVidia had the dinky connector.   
   AMD did not.   
   > Was a patent involved ? Dunno.   
   >   
   > The next thing that happened, is an HDAudio block was placed inside the   
   > GPU. On AMD cards, they didn't want to write their own driver, so they   
   > bought a driver (maybe a RealTek, I forget the branding of the driver).   
   > Maybe AMD actually bought an HDAudio IP block (a logic block designed   
   > by someone else), because AMD no longer enjoys crafting such shit.   
   > The AMD southbridge today, is designed by Asmedia, as an example of how   
   > much they enjoy designing USB host blocks. This all started when the   
   > SB400 had a slower-than-normal USB2 block on it, AMD was ashamed, and   
   > AMD then developed a phobia about doing any more of those. Whereas   
   > NVidia fouled up regularly, made hardware mistakes, held head high   
   > and made their next mistake and so on. You can't let these little things   
   > bother you, in the hardware business. In the rush to market, everyone   
   > is forced to make mistakes.   
   >   
   > Eventually, both NVidia and AMD wrote their own branded HDAudio drivers, and   
   we are   
   > then "at the level of operation standard today". On the Linux side, it   
   > still needs a driver (of course), so some branding of a standard driver   
   > must be present. Most of these "bodge" drivers, all they ever implemented   
   > was stereo, which for a lot of people, is sufficient audio to keep beeps   
   > and alerts and so on. You may find today, the 8ch LPCM, more "modes" are   
   > available, but by default it is likely to be a stereo button. That   
   > could be what you see in my picture.   
   >   
   > Your job, is to dump an inxi -F   
   > and see if the Audio section shares a common characteristic with mine.   
      
   the only exception I can see is:  API: ALSA v: k6.8.0-71-generic status:   
   kernel-api   
   versus yours: API: ALSA v: k6.8.0-51-generic status: kernel-api   
      
   > Now, you didn't say what your video card is, but if your HDMI audio   
   > worked before the upgrade, it should really work after the upgrade.   
      
   I'm assuming the upgrade caused the problem. Is the kernel causing the   
   problem?   
      
   > Even if Nouveau was driving the card,   
      
   It's using the recommended Nvidia 550 driver, but I tried the Nouveau   
   and earlier Nvidia versions also   
      
   >   I think PNP can sniff the existence   
   > of that logic block. It's not like the video driver status "blocks"   
   > the audio. Obviously, if the crossbar is not working in the video card,   
   > and there IS no HDMI signal at all, then a "working" HDAudio block in the   
   > video card can do nothing for you. The HDMI signal has to be working,   
   > as a minimal condition, and your machine should have a picture on the   
   > HDMI monitor.   
      
   video is fine. just no sound :(   
      
      
   >      Paul   
      
      
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