[Pkg-alsa-devel] Bug#814763: HDMI sound not working

[Erik de Castro Lopo]

Package: alsa-base
Version: 1.0.27+1
Severity: important

I have two machines; an Intel NUC i5 and a Dell laptop. Both have
Intel i915 based graphics cards. Both run Debian Testing.

At various times in the past I have used both these machines to
display videos on my TV using HDMI. In both cases, audio that goes
to the TV was transferred over the HDMI cable.

Unfortunately some time in the last 2 months this broke. Both machines
now quite happily display video over HDMI but the audio is missing.
Part of the problem is that I can't remember the details of when it
last worked.

Here's what I know (on my laptop plugged into the TV):

    $ lspci | grep -i vga
    00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core
            processor Graphics Controller (rev 09)

    $ lsmod | grep snd
    snd_hda_codec_hdmi     49152  1
    snd_hda_codec_realtek    81920  1
    snd_hda_codec_generic    73728  1 snd_hda_codec_realtek
    snd_hda_intel            36864  3
    snd_hda_codec           135168  4  snd_hda_codec_realtek,snd_hda_codec_hdmi,
                                       snd_hda_codec_generic,snd_hda_intel
    snd_hda_core             65536  5  snd_hda_codec_realtek,snd_hda_codec_hdmi,
                                       snd_hda_codec_generic,snd_hda_codec,snd_hda_intel
    snd_hwdep                16384  1  snd_hda_codec
    snd_pcm                 102400  4  snd_hda_codec_hdmi,snd_hda_codec,
                                       snd_hda_intel,snd_hda_core
    snd_timer                32768  1  snd_pcm
    snd                      81920  14 snd_hda_codec_realtek,snd_hwdep,snd_timer,
                                       snd_hda_codec_hdmi,snd_pcm,snd_hda_codec_generic,
                                       snd_hda_codec,snd_hda_intel
    soundcore               16384  1 s

Interesting to note that the snd_hda_codec_hdmi driver gets loaded, but it
looks like ALSA doesn't know about it:

    $ cat /proc/asound/cards
     0 [PCH            ]: HDA-Intel - HDA Intel PCH
                          HDA Intel PCH at 0xd1710000 irq 32

To me this looks like a problem with ALSA, rather than higher up like
pulseaudio. I have also tried downreving the kernel to linux-image-3.16.0-4-amd64
and linux-image-4.2.0-1-amd64 but that does help either, which again
points the finger at ALSA.

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (900, 'testing'), (800, 'unstable'), (500, 'testing-updates'), (500, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, armhf, arm64

Kernel: Linux 4.3.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_AU.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages alsa-base depends on:
ii  dpkg  1.18.4
ii  kmod  22-1

alsa-base recommends no packages.

alsa-base suggests no packages.

-- no debconf information