HDMI and alsa

[Wognath]

I recently got a new laptop and had my first experience with hdmi. Since it took me a while to stumble on the right commands, I thought it might save someone some time to post what worked.

Video worked right away (after turning it on with lxrandr) but sound was frustrating. One problem is that alsa-hdmi randomly starts up muted. (You're right, I'm probably doing something stupid, but since I don't know what it is, it's random to me )

When I choose the HDMI option from alsamixer's F6 menu, the alsamixer window shows S/PDIF with a little box above it that has MM in it. I have to hit the M key to toggle MM (mute) to 00,

(link) Many thanks! I might have figured it out for myself in another 6 months or so. Another thing I found out the hard way: sound card must be set before starting vlc, browser, etc.

My goal was for switchover to hdmi to be done by a script that starts a video streaming service from the local library. Preliminaries:

• # alsamixer [F6, set to hdmi card]
  # cp /root/.asoundrc /root/.asoundrc-hdmi [save a copy]
  # amixer -c 0 scontrols
  • Simple mixer control 'PCM',0
    Simple mixer control 'IEC958',0 [By elimination, this one corresponds to the mute]
    Simple mixer control 'SoftPCM',0
    # xrandr -q [find name of HDMI screen]
  Based on that info, my script has these lines to get hdmi up:

  Code: Select all

  xrandr --output HDMI-0 --auto  #switch on HDMI output
  cp -f /root/.asoundrc-hdmi /root/spot/.asoundrc  # spot uses hdmi sound card, root unchanged
  amixer -c 0 set IEC958 unmute   # make sure it's not muted
  run-as-spot browser "--options" "website" 

  If you know a better way to do this, or any good tips, please post.
  
  alsa wiki
  HP 14-an013nr, Fatdog 710 temporarily booting from flash drive
  Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Kabini HDMI/DP Audio. Driver: snd_hda_intel