How to restart ALSA without restarting the raspberry pi itself? - raspberry-pi

I have a Rasperry Pi 3 with an external USB Sound Card. Everything is working fine... sometimes. Some other times the Raspberry Pi is starting up and there is some problem with the sounds system. Sound is not working. When I try to open alsamixer it is saying like "Error while opening the mixer device: No device found" (it's in german... this is the rough translation).
If I get this error, then I have to restart the whole raspberry pi. It would be much nicer if I could just restart alsa somehow. But till now I could not find out how.
OS is Raspbian
Cheers.

This should do the trick
sudo /etc/init.d/alsa-utils stop
sudo alsa force-reload
sudo /etc/init.d/alsa-utils start

Related

It is either cec-ctl or VLC, not both on Raspberry Pi 3 B+ Bullseye

My Node.js project utilizes CEC control and VLC where the app turns on the TV and chooses the HDMI port that the VLC video stream will be viewed on at a scheduled time.
Everything worked on Buster except that too many indeterminate crashes with segmentation faults occur with cec-client.
Since I am nearing a 'production' release, I thought it best to upgrade the OS to Bullseye and find a cec-client replacement. I found cec-ctl and made it asynchronous - ctl-cec works perfectly, everytime, no crashes. BUT, now VLC does not render anything, not even a black screen. Doing a 'ps' command during a time that a video should be playing, I can see that VLC is running.
What I tried: It turns out that changing the /boot/config.txt dtoverlay=vc4-fkms-v3d (Buster) to dtoverlay=vc4-kms-v3d (Bullseye) causes the problem. The Buster version of dtoverlay seems to be required for VLC to run, and The Bullseye version of dtoverlay is required for a /dev/cec0 to be created and used by ctl-cec.
All I can see from my inexperienced view is mutual exclusivity, but this doesn't feel like this is the final answer. Using both dtoverlay version (Buster/Bullseye) will brick the pi (speaking from the very recent experience of one not well-versed in dtoverlays).
I also tried: I Googled this problem to the extent of my search skills and have not been able to resolve this problem.
Any help is greatly appreciated!
Raspbian OS: Bullseye (Desktop)
Raspberry Pi 3 B+
App: Node.js based with ability to make config changes and set schedules via an external browser within the LAN.
The solution for my project, after days of Googling, turned out to be TOO simple (found here: https://www.reddit.com/r/archlinuxarm/comments/lg4z5u/no_hdmi_audio_via_alsa_on_raspberry_pi_400/):
sudo apt install pulseaudio
along with:
dtoverlay=vc4-kms-v3d
VLC and cec-ctl now work together perfectly on Raspberry Pi 3B+/Bullseye

Want to understand the different possibilities to autostart a program on a Raspberry Pi

I've a raspberry Pi with a actual Buster OS and a Rhasspy installation. Rhasspy requires a working audio environment, in my case a seeed Respeaker 2Mic-Pi HAT and a bluetooth speaker. Starting Rhasspy manually works without any problem, but all my attempts with a Buster light OS to start Rhasspy automatically didn't work. I tried to start Rhasspy with a cronjob #reboot, with rc.local and as a service but either the 2Mic-Pi HAT or the Bluetooth speaker didn't work. My final attempt was with a Buster Desktop installation. Same thing as with the light installation except when I start Rhasspy with a .desktop file that at least did the thing. So I want to know what makes the difference here compared with my unsuccessful attempts. Thanks in advance for a clarification... Jo

raspberry pi 4 onboard virtual keyboard AT-SPI: Couldn't connect to accessibility bus. Is at-spi-bus-launcher running?

I installed "onboard" as a virtual keyboard on the system. It looked much nicer and more useful than matchbox. I went into the settings and chose the auto open option when I edit the post. after that i restarted my raspberry pi. As it didn't come on automatically, I couldn't run it from the terminal or the menu normally. The error I get when I try to run it from terminal
Hej blackmamba,
I had the same issue with the on screen keyboard florence. After I installed at-spi2-core, it didn't crash anymore, though i could not get it to open automatically.
So I tried installing onboard and everything worked quiet well. Might be a hint..
regards, jarvis
Raspberry Pi B+
5.10.63 Kernel
Debian Buster 10
Waveshare 10.1" HDMI LCD Touch Display

Raspberry Pi 3 A+ distorted/screeching audio when using ALSA + Jackd2 through on-board headphone jack

I am trying to set up Supercollider on my Raspberry Pi 3 A+ on Raspbian Lite using this guide. Jackd2 and Supercollider both compile fine, and there are no errors when I try to run Supercollider or the jack_simple_client test. However, regardless of different sample rates, buffer sizes, number of periods etc. used in booting the jack server the audio always comes out heavily distorted, with loud high pitched squealing and low popping noises.
Using the speaker-test command from ALSA creates a clean, non distorted test tone. Previously trying pyo as a DSP module would also suffer from the same issue if I used Jack, but would work fine otherwise. This leads me to believe that there is some issue in the communication between jack and ALSA. Power supply is likely not the problem as well. My installed jack version is 1.9.17 and ALSA is k5.4.83-v7+. I am new to working with Linux audio/Jack, so any help is much appreciated!
Things I would try:
Try jack2
Get a fresh SD card, and use the version of jack that comes with raspbian and then either try building again or just trying to also get SuperCollider via apt.
sudo apt-get install cmake libasound2-dev libsamplerate0-dev libsndfile1-dev libavahi-client-dev libicu-dev libreadline-dev libfftw3-dev libxt-dev libcwiid1 libcwiid-dev subversion libqt4-dev libqtwebkit-dev libjack-jackd2-dev
Check how it sounds out of the HDMI port or a USB audio adaptor or a hat. The headphone jack tends to sound terrible anyway on raspberry pis, so if something else works, that's you answer.
I've been working with Alsa around 4 years ago, but remember I had the problem.
First I thought that my device was the reason, and it turned out to be that the noise was coming from wrong channel, and I had to force set alsa channels manually with cli commands and later in config files.
Try to check that alsa does not assign wrong channel when Jack is up.

Raspberry pi freeze when trying to install vlc

I am trying to install vlc on my raspberry pi 3. Using sudo apt-get install vlc. The process starts, but eventually freezes. This is the only time it freezes and it does so every time I try. Cant reboot through ssh either. I use the official stontronica power supply, so doubt that is the problem.
Any help is much appreciated