Arch Linux

acez

Member

Registered: 2015-09-23

Posts: 2

Choppy mouse pointer on 4K display

Hi,

    I have a thinkpad t540p running Archlinux and I am having some small issue. Basically the problem is that when I move the mouse accross the screen it is a bit choppy. It doesn't seem like there is any lag or delay but just that the mouse pointer isn't moving smoothly and fluidly across the screen. It is not very pronounced but just enough to be annoying. I am using 2 4K Dell P2415Q monitors and using both at a 4K/60hz. Only one is plugged in my laptop and the other one is connected to that one through daisy chaining (MST). At first I thought the issue was being caused by the fact that outputting 2x4K at 60hz would be tough for the laptop but that is not very likely to be the case; I can watch hd videos on the monitors and they don't show any sign of choppiness or lag or anything like that. The only issue is that the mouse pointer doesn't move smoothly. Moreover this issue seems to only be present when I am using MST. The reason I believe that is that I have tried disabling MST on one of the monitors and on that one, there was no choppy mouse issue but as soon as I moved the mouse across to the other monitor running with MST enabled I could clearly see that issue there. Also the issue didn't seem to be present when the resolution was less than 4K.
    For those of you wondering how I was able to disable MST on the monitor plugged in directly to my laptop and still be able to use the other monitor: I used a docking station. One monitor was plugged in to my laptop so didn't need MST, the one plugged into the docking station needed MST enabled since the thinkpad docking station uses an internal MST hub.

    Anyway, I would appreciate any help with this. Everything seems to be working fine except for this choppy mouse movement (whether USB or trackpoint or touchpad) and like I said there doesn't seem to be any lag in the mouse pointer movement: it is moving at the expected speed but it's just choppy (almost as if it was skipping pixels).

Thanks,
    acez

Last edited by acez (2015-09-23 07:00:27)

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: Choppy mouse pointer on 4K display

Try mouse polling rate.

acez

Member

Registered: 2015-09-23

Posts: 2

Re: Choppy mouse pointer on 4K display

Hi, thanks for the tip but it didn't work