Doom 3 (original not BFG) has a regression that makes it impossible to control (mouselook) since Proton 9 Issue transferred from https://github.com/ValveSoftware/Proton/issues/9007. @Deus-nsf posted on 2025-08-26T19:12:10: I must clarify that I'm on the SteamDeck (even though that shouldn't really change much). Reverting to Proton 8 fixes the issue, but more recent Proton are useful for some featu...
There was a major push that was made on the stable SteamOS branch recently, and I saw many occurences in the changelog mentionning the compositor and frame delivery, and how it would apparently fix things mostly for VRR....
For science I updated the Proton Exp build which is still configured with the bleeding edge branch, and the fix seems to hold so far :) Now I have to really do something about that micro stutter issue (not doom 3 related...
@Deus-nsf Thank you for the feedback and the testing!! I don't play this game regularly, so it is great to know that it seems completely fixed. We might iterate on this fix a bit more as it was actually fixing a regressi...
Thanks a lot for taking a look at this again, when I mention "original engine", it just means that it's the vanilla default engine that ships with the Steam release, I mentionned it because there's several quality source...
@Deus-nsf Also - could you please try the experimental "bleeding-edge" branch? You will need to manually select "bleeding-edge" as the beta option for Proton - Experimental. A different regression was just fixed this wee...
@Deus-nsf Thank you for the confirmation! I took another look and I'm not noticing any difference between 8.0 and 9.0 ... I saw you mention multiple times that you are using the original engine ... is this an option I ne...
Yes! It is this exact issue, as far as I can remember it does it on stock 9.0-4, let me double check and get back to you (will edit this comment). EDIT: it looks like stock 9.0-4 doesn't have this issue, but an other one...
@Deus-nsf Could you please try stock 9.0-4 and see if this build has the mouselook issue that you are describing? I *think* I see the same thing as you, but I cannot reproduce it on 9.0-4 or experimental-9-bleeding-edge ...