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I’ve got a Lenovo Legion 5 Pro and I use an external monitor. I’m experiencing horizontal screen tearing when I scroll down/up and when I watch movies or youtube videos. This does not happen when I use the laptop’s screen. The external monitor is connected to the HDMI port.

System info:
AMD Ryzen 7 5800H with Radeon Graphics
NVIDIA RTX 3070 with Nvidia 470
Kernel 5.11.0-34-generic #36~20.04.1-Ubuntu SMP Fri Aug 27 08:06:32 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

I’ve got my system set to Nvidia Performance mode. If I set Power saving mode the monitor is not detected. If I set Nvidia On Demand, graphical performance on the external monitor slows to a crawl.

I’m looking for a solution for eliminating the screen tearing on the external monitor. It doesn’t matter if that solution switches off the Nvidia graphics card or not.

Thanks

2 Answers 2

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I found a solution. Enabling "Force Full Composition Pipeline" eliminates screen tearing on the second screen.

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I have the same laptop and I experienced a similar problem after I upgraded the kernel. To solve it, I downgraded the kernel to 5.11.0-31-generic (if you don't have it, install it with apt install linux-headers-5.11.0-31-generic (I'm not sure if you need to install some other things as well, like linux-image-5.11.0-31-generic, or if it will happen automatically).

Other things to make sure:

  1. For met the external monitor works best with the nvidia propietary drivers and in the "Nvidia on-demand" setting
  2. Make sure you select the Dynamic graphics mode in the bios (press F2 on start-up. I had to update the bios before that option showed up)
  3. I used this redit post for my setup. I didn't have to add the PPA for a new kernel, because I'm on 21.04, but here are some quotes that helped me:
    • In the BIOS (F2 at lenovo screen) must set to HYBRID mode (now renamed to dynamic graphics mode, I think)
    • edit grub and add the entry amdgpu.backlight=0 to fix backlight control of the original monitor
    • Tip: Gnome users can use this extension to change nvidia or integrated mode easy: https://extensions.gnome.org/extension/1275/prime-indicator/
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  • On a side note: the only problem I still have is that some applications (I think electron applications like the Element and Rocket.Chat desktop apps) are super slow on the external monitor but not on the internal monitor. This really freaks me out. I also noticed that fractional scaling is not (yet) supported if you use the "Nvidia only" mode. Sep 15, 2021 at 14:31
  • Thanks for trying to help, but it didn't work. Nvidia on demand causes poor performance in the second monitor. I do not have brightness control issues on my machine with the current drivers and kernel version. Sep 16, 2021 at 7:52

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