Noises from laptop with Slackware (14.2 and -current)
 

Bit of a long shot, but I've noticed that both Slack 14.2 and -current when installed on my Librem 15 produce quite a bit of noise from the machine. It's odd, but touching the trackpad creates a quiet but noticeable electrical sound, and even scrolling on Firefox does it (slightly different sound but definitely audible). However, it goes away completely if I install Void Linux, so it's not a hardware issue as I was initially thinking.

Just throwing this out there in case anyone has any ideas about what might be causing it on Slack??

Could be a few things.

have you checked the refreshrate of the monitor (xrandr)? Or you could also see what happens if you set screen brightness to 90 or 80 percent. (xbacklight -set 80, or as root intel_backlight 80), since it might be one of the capacitors. Because the way you describe the sound it seems a capacitor issue, because some setting/driver is pushing it over the limit by for example too much powerconsumption, or just 100percent powerconsumption. It often happens with cheaper or faulty tn panels, which is not a problem, as long as you don't push it to the max.

edit: what you could also try, if the noise doesn't go away with the above, it setting the volume of your speaker to 0, because it might also be static noise.

install lm_sensors and check your cpu temp

then google your cpu model/laptop model and fins out the average temperature in the tests they did

compare them with that. then pick apart your laptop and clean it from dust



google throttling of your cpu and/or check power management features regarding cpu?

*also why the heck does touching your trackpad make an electrical sound!?
*actually just write sensors in terminal, its was installed for me already

I'll try some of these things out and report back. But the laptop is brand new (no dust), and I'm very sceptical that there's a hardware problem, considering it only manifests in Slackware and not at all in Void. It's not super loud, but it's noticeable enough to be annoying. On Slackware it will be buzzing away constantly (with additional noise when the trackpad is touched or when scrolling in Firefox; no doubt other things too), on Void it's nearly totally silent. It's pretty surprising to me, but something is doing it and it's definitely software-based. I might test a couple of other distributions, just out of interest.

What is the make and model of your computer? Does your computer have an Intel chipset manufactured in the past couple of years (Skylake or newer)? Sounds like "coil whine" from your description.

My Dell XPS 13 makes a faint noise when I scroll up and down in the web browser. Sounds kind of like chattering squirrels.

https://www.youtube.com/watch?v=blyswNKEPEY

It's a Librem 15 v4, so Skylake (Core i7 7500U) with Intel HD 620 for graphics.

The sound from that YouTube clip sounds a lot like it!

Odd that it's quiet in Void Linux! I wish I had an explanation.

Strange, and I get it too on an Asus Zenbook. I hadn't thought much about it before, but I tested booting into Centos7 and it's basically quiet. Booted into Slack -current though, it's that very soft electrical sound.

It's present in this laptop as ongoing background chatter. Dimming or turning off the monitor, speaker and keyboard backlight make no difference.

Launching a web browser makes it loudest, which made me think it's tied to wifi activity but I can't say.

It's pretty faint for me, but odd indeed.

Have you tried putting CPU scaling governor on powersave in Current?

Nice, that's what it is! Switching the scaling governor to "powersave" (for all the CPUs) reduces the noise down to a level that is barely audible:
So looks like it's actually a combination of hardware (thanks snowpine) and software (thanks RadicalDreamer).

I'll mark this as solved.

Nice detective work! I will give it a try on my XPS 13. :)