Legion Go S (Z2 Go Glacier) D-Pad Randomly Drops Inputs

[LumpyArbuckle]

Steam Version - 1782533657
SteamOS Version - 3.8.12
Opted into Steam client beta? - No
Opted into SteamOS beta? - Yes
Have you checked for updates in Settings > System? - Yes

When using the D-Pad, inputs will randomly stop working, it doesn't matter how hard you press it, it simply just stops responding. It's not a game specific issue either as it occurs in multiple games, not only that, but you can also press the Steam menu button and have the menu pull up, something that you usually cannot do when holding down a D-Pad input, leading me to believe that the entire OS is not detecting that that input is being pressed. The input will never be recognized again until I let go of all D-Pad inputs entirely.

I've also tested Bazzite, and it doesn't appear to have this problem.

[LumpyArbuckle]

I'm not sure if this is allowed, I apologize if it's not, I just thought I should add more information and a few other reports of this issue, in hopes that the issue one day gets solved. I haven't seen any mention of it in the recent SteamOS updates so I assume it has not been just yet.

Video of the Problem - https://www.youtube.com/watch?v=cwpGsF_RpF0

Other Users With the Problem - https://www.reddit.com/r/LegionGo/comments/1ufmwpb/right_input_on_legion_go_s_dpad_frequently_locks/
https://www.reddit.com/r/LegionGo/comments/1u2zdyp/is_it_me_or_the_dpad_in_the_legion_go_s_is_awful/
https://www.reddit.com/r/LegionGo/comments/1ufmwpb/right_input_on_legion_go_s_dpad_frequently_locks/

[pastaq]

Steam Version: 1783556394
SteamOS Version: 3.8.22
Opted into Steam client beta? - Yes
Opted into SteamOS beta? - Yes
InputPlumber version: 0.77.7
Proton: Experimental Jul 2 2026

I started looking into this. I have been able to reproduce it a few times and I found some interesting results. The reproduction rate is really low for me (maybe 1 time out of every 40 mins of gameplay).

In this screenshot dpad right was not working. You can see hat hatx is 1 and then immediately 0. Up and down (hat y 1/-1) are working.
https://github.com/user-attachments/assets/13c7737e-923c-459e-a89b-83060dc531ff

In this video I reproduced the issue exactly. You can see from the inputplumber device 0 test I have running on the laptop in the background over SSH, the up event is clearly triggered there, but the event is not working.

https://youtu.be/hew9M1tfExo

What appears to be happening is a fairly difficult to hit case where the perfect storm of events hits exactly as a poll of the virtual steam deck target device is occuring. The Legion Go S can sometimes have some chatter if the pressure is just right on a dpad input; wherein a down, up, then down event all hit in the same event frame. These are all forwarded to the steam deck target device which has a state de-bounce functionality to prevent a null change (down then up in the same frame would cancel out and have no event). The "up" event triggers too fast so it is delayed, as intended, then the second down event hits and is a "no-op" so there is no state change. In the following frame the "up" event that was delayed is then triggered, which causes the virtual device to get out of sync with the physical hardware and doesn't re-sync until the button is cycled again. The fix appears to be to clear the delayed "up" event if it is overwritten by a state change before its resend timer has expired.

I have a potential fix I'm testing, but the low reproduction rate is making validation a challenge.

[LumpyArbuckle]

The issue triggered far more often than that for me, I would say at least once every 10 minutes or so. I'm not sure if there's any easy way to apply that fix to my system so I could help validate it, but if there is then I'd love to help.

[pastaq]

I can ask @KyleGospo to grab this InputPlumber patch for the next Bazzite Testing, which should allow you to validate it without reinstalling your system.

[LumpyArbuckle]

Bazzite? Bazzite doesn't have this issue for me, just SteamOS, are you also having this problem occur on Bazzite?

[pastaq]

Bazzite? Bazzite doesn't have this issue for me, just SteamOS, are you also having this problem occur on Bazzite?

Bazzite is switching to InputPlumber in the next version.