Hi,

I have a problem with Debian on a Compaq Presario C500 with SynPS/2 Synaptics mouse.
The mouse is kind of slow and doesn't spam the whole screen in one movement, as it should do.
Even if I change acceleration to 10 with the XFCE control, it still behaves the same way.
This issue is present both in Debian Stretch and Buster whereas it is absent in other distros I have installed on the same laptop, even Debian based ones like MX16.
In the other distros, an acceleration 2 0 is enough for the mouse to function perfectly.
I checked the Debian wiki and I have the recomended xserver-xorg-input-libinput package installed.

Any suggestion?

i will assume you are talking about a touchpad here, since you mentioned synaptics?

first of all, let's make sure if the synaptics or libinput driver is in use.
enter
just like that and post the output.

bash: synclient: command not found

I installed the package xserver-xorg-input-synaptics.
Then the output of sylclient was:

Couldn't find synaptics properties. No synaptics driver loaded?

you might need to restart the graphical session, and try again.
while you're at it, also if you want to investigate yourself, read xinput's man page.

$ synclient
Parameter settings:
LeftEdge = 1752
RightEdge = 5192
TopEdge = 1620
BottomEdge = 4236
FingerLow = 25
FingerHigh = 30
MaxTapTime = 180
MaxTapMove = 221
MaxDoubleTapTime = 180
SingleTapTimeout = 180
ClickTime = 100
EmulateMidButtonTime = 75
EmulateTwoFingerMinZ = 282
EmulateTwoFingerMinW = 7
VertScrollDelta = 100
HorizScrollDelta = 100
VertEdgeScroll = 0
HorizEdgeScroll = 0
CornerCoasting = 0
VertTwoFingerScroll = 1
HorizTwoFingerScroll = 0
MinSpeed = 1
MaxSpeed = 1.75
AccelFactor = 0.0398089
TouchpadOff = 0
LockedDrags = 0
LockedDragTimeout = 5000
RTCornerButton = 0
RBCornerButton = 0
LTCornerButton = 0
LBCornerButton = 0
TapButton1 = 0
TapButton2 = 0
TapButton3 = 0
ClickFinger1 = 1
ClickFinger2 = 1
ClickFinger3 = 1
CircularScrolling = 0
CircScrollDelta = 0.1
CircScrollTrigger = 0
CircularPad = 0
PalmDetect = 0
PalmMinWidth = 10
PalmMinZ = 200
CoastingSpeed = 20
CoastingFriction = 50
PressureMotionMinZ = 30
PressureMotionMaxZ = 160
PressureMotionMinFactor = 1
PressureMotionMaxFactor = 1
GrabEventDevice = 0
TapAndDragGesture = 1
AreaLeftEdge = 0
AreaRightEdge = 0
AreaTopEdge = 0
AreaBottomEdge = 0
HorizHysteresis = 25
VertHysteresis = 25
ClickPad = 0

$ xinput
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=10 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Video Bus id=7 [slave keyboard (3)]
↳ Power Button id=8 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=9 [slave keyboard (3)]
↳ HP WMI hotkeys id=11 [slave keyboard (3)]

Installing xinput actually solved the problem.
The mouse is functioning properly now.
I will add these packages to my list of "basic apps to install" for Debian.
I'll mark this as solved, albeit if someone cares to elaborate about what caused the issue, that'd interesting.
Thanks for the help.