On Mon, Mar 14, 2022 at 09:36:08PM +0100, Roland Freikamp wrote: > Hi, > > I have a problem with the input-system: > - X suddenly stops to accept touches from a touchpanel > (connected via USB). > - Re-connecting USB re-enables the touchpanel. > - "xinput disable 7; xinput enable 7" (7=id of the touchpanel) also > re-enables the touchpanel. > > It looks like the input-events of the touchpanel suddenly stop to be > propagated to the "Virtual core pointer": > - "xinput list --long 7" still shows the touches and correct positions > - but the positions in 'xinput list --long "Virtual core pointer"' are frozen > > Any ideas/hints?
two possible causes I can think of: - a stuck grab on the device itself (unlikely since virtually nothing grabs devices directly). stuck grabs are fun to debug (fsvo "fun"), unless you have a reliable reproducer it's virtually impossible. - the device loses track of touch events and either the device or X thinks that there is more than one touch down. Happened frequently with older touchpanels. You can verify that by running libinput record --autorestart (see the man page) and check the most recent recording(s) when it happens. If you see BTN_TOOL_DOUBLETAP appearing when you have only one finger down, the issue is in the device itself. Cheers, Peter
