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Tomasz Giba
Tomasz Giba

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Lenovo ThinkPad L14 Problem booting Ubuntu 20.10 (Kernel 5.8) with Ryzen 7 Pro 4750U

I got my ThinkPad L14 this year (2020)
When I upgraded my Ubuntu from 20.04 to 20.10 I encountered blank screen.

In booting logs I saw this error:

AMD-Vi: Unable to read/write to IOMMU perf counter
Enter fullscreen mode Exit fullscreen mode

and inspired by this Stackoverflow answer

I did the following:

  • in your GRUB boot menu select Advanced Ubuntu
  • select your previous (working) kernel version, mine was 5.4
  • log into Ubuntu
  • edit GRUB sudo vim /etc/default/grub
  • change this line GRUB_CMDLINE_LINUX="iommu=soft" and save the change
  • run sudo update-grub
  • restart and select your updated Ubuntu with kernel version 5.8

And it works!

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