Terminal input lag on Lenovo Ideapad (AMD 8845HS, 780M GPU)

General
1

Hello

Wanted to try CachyOS. Previously had Tuxedo OS installed.

Unfortunately, I have an issue where my key inputs in the terminal only appear when I move the mouse. I don’t notice this problem in Firefox or other applications.

Even if I type something and press Enter, nothing appears until I move the mouse. The same happens when I use the arrow keys on the keyboard.

I’m using a Lenovo Ideapad with an AMD 8845HS and a 780M GPU.
Setting rcutree.enable_rcu_lazy=0 brought only minor improvements—at least I no longer need to move the mouse, but it’s still not smooth.

The CPU is set to performance mode, as recommended in the Wiki under *General System Tweaks

Testet Kernel

6.10.2
6.12.10
6.12.13 lts
6.13.2 normal AMD BMq, bore, eevdf
6.14 rc1

Thx daniel

Edit:

danielf@cachyos-x8664
OS: CachyOS x86_64
Host: 83DS (IdeaPad 5 2-in-1 16AHP9)
Kernel: Linux 6.13.2-2-cachyos
Uptime: 16 seconds
Packages: 1175 (pacman)
Shell: fish 3.7.1
Display (SDC41A7): 2048x1280 @ 120 Hz (]
DE: KDE Plasma 6.2.5
WM: KWin (Wayland)
WM Theme: Breeze
Theme: Breeze (Dark) [Qt], Breeze-Dark
Icons: breeze-dark [Qt], breeze-dark [G]
Font: Noto Sans (10pt) [Qt], Noto Sans ]
Cursor: capitaine (24px)
Terminal: konsole 24.12.2
CPU: AMD Ryzen 7 8845HS w/ Radeon 780M z
GPU: AMD Phoenix3 [Integrated]
Memory: 1.68 GiB / 14.39 GiB (12%)
Swap: 1.25 MiB / 14.39 GiB (0%)
… Disk (/): 16.36 GiB / 463.42 GiB (4%) -s
Local IP (wlan0): 192.168.178.129/24
Battery (L23C3PE1): 100% [AC Connected]
Locale: de_DE.UTF-8

2

which desktop environment and wich terminal emulator?

3

KDE and Gnome with the default installed terminal.

4

We generally assume that it is KDE because that is the default setting.

Categories should be created for all the other DEs that CachyOS offers so that unnecessary questions are no longer necessary.

In short: users who are interested in a quick solution should not have to ask unnecessary questions.

Mayday, mayday, Cathey is falling to the ground. I urgently need it for my state exam tomorrow. Help, now!

5

@D_V Which terminal? Alacritty? Try an alternative maybe?

I have a similar ideapad, I don’t have these issues. Do you have https://wiki.archlinux.org/title/Variable_refresh_rate enabled? I had similar issues playing videos with vrr enabled on gnome. The videos had low refresh rate if I didn’t move the mouse.

Agreed, I like how endeavourOS did the categories. For example I don’t know much about KDE, so it would save some back and forth, before I realize I can’t help much.

1 Like
6

I was able to partially fix the issue.

I had to set processor.max_cstate=1, and the power mode must be set to performance. With these settings, everything runs smoothly. When switching to balanced, input lags slightly but is not as bad as before, and I no longer need to move the mouse for text to appear.

I suspect that the kernel and power management are not handling the CPU properly.

7

Did you check if vrr is enabled? In gnome there’s a switch somewhere in the settings app

8

I searched in KDE but couldn’t find anything. I have a laptop with an iGPU—could it be different in that case?

9

mine has an iGPU too Lenovo IdeaPad Slim 3 15ABR8

10

I installed CachyOS with Gnome on another M.2, and I can’t find the option to enable VRR. I’m at a loss; the processor.max_cstate=1 option no longer helps. für 6 Sekunden

I installed CachyOS with Gnome on another M.2 and don’t see any option to configure VRR. I’m at a loss; the processor.max_cstate=1 option no longer helps.

Edit: I already noticed the lag during installation. Then, at the login screen when entering my password, I noticed it as well. I have 12 characters, but they only become visible after moving the mouse.

11

Ive seen this exact behaviour on 2 different intel alderlake systems. Maybe not AMD related?

12

Seems like a kernel issue. I installed Fedora 41 and have the same problem. However, when I install Fedora 40 (Kernel 6.8.9), the issue doesn’t occur.

Is there a way to test Kernel 6.8.9 on CachyOS?

13

I found the page with the releases and went through them month by month. With the November release (6.11.7), I booted the USB installation and had no input lag in the terminal.

When I start the installation, I get a message saying that I should install a newer version. A window still opens and starts the installation.

Is there a way to stay on the older version for now?

14

You could turn off the internet during install. Did you try the LTS kernel?