I have a new laptop, a birthday present to myself last month. For once, rather than buying a cut-rate netbook, I decided to treat myself to a fancy Lenovo Carbon X1 with an up-to-date processor and lots of RAM.
Since I have way more resources than I'm used to, I decided I'd try installing a full Ubuntu and not trying to pare it down to a super lightweight system. I'm still running the lightweight, fast, highly configurable Openbox window manager instead of a full Gnome desktop: Openbox does just what I tell it and no more, and doesn't surprise me with random redesigns. But I did let Ubuntu install some system utilities I've always avoided in the past, like NetworkManager and PulseAudio. I decided I'd give them a chance, see if they've gotten better since I last checked.
They have, though they're still a bit of a hassle to deal with. NetworkManager can be controlled through nmcli, which is poorly documented but works okay if you google long enough to find the proper incancations. PulseAudio gave me a bit more trouble.
The standard GUI for controlling PulseAudio is
It showed two audio devices: "USB PnP Audio Device Analog Stereo" and
"Built-in Audio Analog Stereo". Turns out the USB PnP option is a
sound card built into the USB hub, a Totu tt-hb003a 11-in-1 USB-C hub
that lets me connect to a charger, external monitor, SD and micro-SD
slots, and extra USB ports without juggling a lot of extra cables.
Pulse assumes -- probably reasonably, though it's wrong in this case -- that if I have a USB audio device connected, I probably want to use it in preference to the laptop's built-in audio. That would make sense if I had external speakers plugged in, but I left all my computer speakers behind when I moved. I should probably order some speakers. But meanwhile, I needed to persuade PulseAudio to ignore the hub and use the laptop's built-in sound system.
Mute/Unmute via the Keyboard
The Lenovo, like most laptops, has a dedicated key for muting, Fn-F1.
It even has a little light on it to show whether it's muted. In
Openbox, pressing Fn-F1 actually muted the sound, and even turned on
the light. This is probably because I'd previously set
key="XF86AudioMute" to run
amixer set Master toggle
in .config/openbox/rc.xml, which worked on my Pulse-free
pared-down Debian netbook. The problem is that pressing iFn-F1 again
didn't bring the sound back. Instead, it was unmuting the USB hub's audio.
Clicking "Set as fallback" on the built-in audio in pavucontrol made
It turns out that it is virtually impossible to persuade PulseAudio to use "Built-in Audio" when a "USB PnP Audio Device" is available. I finally found the secret: in pavucontrol's Configuration tab, set Profile for the PnP USB device to Off. Now only the built-in device shows up in the other tabs.
But that amixer command still wasn't unmuting properly, so the next
step was to find a command that would actually unmute. Someone on
pactl set-sink-mute @DEFAULT_SINK@ toggle
and that worked great from the command line. But when I tried to bind it
in Openbox to the XF86AudioMute key, it did nothing. I still
don't understand why not; I wasted a lot of time comparing my
shell environment to openbox's environment and never found the
Back to web searching, I found an askbuntu thread suggesting some Openbox stanzas. In particular, it apparently works better to use alsamixer rather than pactl. This finally worked for toggling mute:
<keybind key="XF86AudioMute"> <action name="Execute"> <command>amixer -q -D pulse sset Master toggle</command> </action> </keybind>
Volume Controls via Function Keys
Partial success! Unfortunately, the volume control commands in that
same askbuntu post,
amixer -q -D pulse sset Master 3%+ unmute,
did nothing. I had already noticed that in pavucontrol, the volume
controls didn't work either. In fact, if I started some music playing
and then called up alsamixer, channels like Master and Speaker didn't
do anything; the only channel that affected volume was ALSA PCM. After some
fiddling, I discovered that I had to change Master to PCM and
remove the -D pulse:
<keybind key="XF86AudioRaiseVolume"> <action name="Execute"> <command>amixer sset PCM 4%+ unmute</command> </action> </keybind> <keybind key="XF86AudioLowerVolume"> <action name="Execute"> <command>amixer sset PCM 4%- unmute</command> </action> </keybind>
I'm sure I'll eventually need to fiddle some more. For one thing, if I ever want to use audio during a talk (as I did briefly at my Stonehenge talk earlier this year) I'll need to figure out how to enable a temporary HDMI sound sink quickly without needing to fiddle with pavucontrol. But for now, I'm happy to have the basic laptop volume and mute keys working.
[ 15:43 Nov 24, 2019 More linux | permalink to this entry | comments ]