In my original comment I was referring to people asking about various mouse fix/cpl fix programs that are supposed to remove acceleration (I wasn't commenting on rawinput). Those programs were what I was talking about when I said you never needed them as unchecking EPP and using -noforce commands was adequate and easier. Also, I was only referring to CS since other games also had built in accel and no -noforce commands.
Rawinput is different and bypasses all windows interference with mouse movement which includes removing windows' acceleration.
After reading the 2nd post
Oh, sorry, I didn't know CPL mouse fix was created for quake... I thought we were talking about counter-strike.
Hmm, I see where there might be some confusion. When he says "They DO NOT add any option to disable accel" he means that within the game alone you cannot disable acceleration. You must also uncheck EPP.
>When MouseSpeed=0, no accel was applied
>They add a -noforcemspd launch option to NOT set MouseSpeed=1 //In other words, the game won't turn on EPP, but if EPP is checked then you'll still have accel in-game.
In the end when he's talking about "m_mousespeed 0" in the source engine, he's still talking about trying to disable mouseaccel completely from within the game only. I'm not sure why he cares so much about this. Maybe he wants to use EPP in windows but not ingame...
This is my understanding but I may have missed something.