Some issues on Lenovo YOGA C940


Fedora 30 runs pretty well on this Laptop, but it does have some issues that I need help with:

  • I get exactly two messages on every boot saying that the kernel image crashed. The log entry is called “xorg-x11-drv-intel” and stated reason is “WARNING: CPU: 6 PID: 404 at drivers/gpu/drm/i915/intel_cdclk.c:1889 icl_calc_voltage_level+0x47/0x80 [i915]”
  • The screen glitches every few seconds, basically it shifts to the right and back again. Mostly for just a split second, but sometimes it stays shifted until I interact with the system again (e.g. move the cursor). Sometimes it’s accompanied by horizontal green lines across the screen, and sometimes it doesn’t happen at all for minutes or even hours. Here is a short video of it (at 0:05): Graphical glitches on Fedora 30 - YouTube
  • I can’t enable bluetooth. I can flip the switch in settings back and forth, but the screen always says that it’s switched off.
  • The shell randomly stops responding to input (mouse and touch) when using the touchscreen. The keyboard and apps on screen keep working, and logging out and back in usually fixes it.

System: Lenovo YOGA C940-13IIL, Intel Core i7-1065G7, Intel HD Graphics (Ice Lake 8x8 GT2), Kernel 5.2.15-200.fc30.x86_64, Fedora 30, Gnome 3.32.2 Wayland

I would really appreciate some advice and/or pointers in the right direction.

Cheers =)

I also have a Yoga C940. I’m running 31 and I’m not having as many problems.

Have you been able to get the internal microphones and the other speakers to work?

Yea the upgrade to 31 fixed some things, but not all. Bluetooth works now without issues, and the screen shifting thing barely happens anymore (though it does still happen sometimes!). Speakers are hit-or-miss in my experience, sometimes they work, sometimes just one stereo channel works, and sometimes they don’t work at all, and I have no idea what’s causing it. :confused: The build-in microphone never works, I can’t even select it as recording device in the settings.

The microphones are connected in a different way that requires a different driver. There is ongoing work to have this different way (SOF project) work for this machine.
The other speakers might be connected through the Realtek ALC 289. The ThinkPad X1 has a similar setup and it is working. I’m trying to find out how it works.

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