Tapped events lost sometimes

[HakanL]

I have a RPi solution, Skia Framebuffer with a touch screen. There are times when I clearly tap the touch screen (I log the touch event), but the button/card click event isn't fired. So I tap it again and then it works (but other times it works the first time, or the 3rd time). I haven't been able to reliably reproduce it, but it seems that it especially happens at cold start. I was thinking maybe it somehow thinks that I'm dragging (scrolling) if I slightly move my finger when I touch? Where would I start to figure out why the click events (sometimes) aren't fired?

[sasakrsmanovic]

I wonder if @pjgpetecodes has come across this during his Pi exploration.

[HakanL]

I haven't been able to try it on 5.0 yet (due to this: #13796 (comment)). But I added logging to 4.10.

This is when the tap did not register as a tap:

17:55:52.068 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_DOWN, pointerId:0, currentPosition:[258, 88], timestamp:854647152169
17:55:52.084 VRB [DMXCore.DMXCore100.App] Pressed at 258:88 Contact: True
17:55:52.085 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerPressed [Grid-00B6333C]
17:55:52.086 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_MOTION, pointerId:0, currentPosition:[257, 88], timestamp:854647170526
17:55:52.087 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Ignoring captures] raising event Pressed (args: 00E79B72) to original source [Grid-00B6333C]
17:55:52.089 DBG [Uno.UI.Xaml.Core.PointerCapture] ScrollContentPresenter-00E6CEC1: Capturing (Implicit) pointer Touch/0
17:55:52.090 DBG [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] SetPointerCapture not supported on Skia for FrameBuffer.
17:55:52.091 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerMoved [Grid-00B6333C]
17:55:52.092 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Ignoring captures] raising event Enter (args: 0179778F) to original source [Grid-00B6333C]
17:55:52.146 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_UP, pointerId:0, currentPosition:[257, 88], timestamp:854647207123
17:55:52.151 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 0179778F) to original source first [Grid-00B6333C]
17:55:52.151 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 0179778F) to capture target [Grid-00B6333C] (-- no bubbling--)
17:55:52.153 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerReleased [Grid-00B6333C]
17:55:52.153 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Released (args: 02DD91EA) to original source first [Grid-00B6333C]
17:55:52.153 DBG [Uno.UI.Xaml.Input.FocusRectManager] Hiding focus rect
17:55:52.159 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Released (args: 02DD91EA) to capture target [Grid-00B6333C] (-- no bubbling--)

and this is when it registered:

17:55:56.939 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_DOWN, pointerId:0, currentPosition:[275, 92], timestamp:854652023148
17:55:56.949 VRB [DMXCore.DMXCore100.App] Pressed at 275:92 Contact: True
17:55:56.951 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerPressed [Grid-00B6333C]
17:55:56.952 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Ignoring captures] raising event Pressed (args: 019CE583) to original source [Grid-00B6333C]
17:55:56.953 DBG [Uno.UI.Xaml.Core.PointerCapture] ScrollContentPresenter-00E6CEC1: Releasing (Any) capture of pointer Touch/0
17:55:56.953 DBG [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ReleasePointerCapture not supported on Skia for FrameBuffer.
17:55:56.954 DBG [Uno.UI.Xaml.Core.PointerCapture] ScrollContentPresenter-00E6CEC1: Capturing (Implicit) pointer Touch/0
17:55:56.954 DBG [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] SetPointerCapture not supported on Skia for FrameBuffer.
17:55:56.960 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_MOTION, pointerId:0, currentPosition:[274, 92], timestamp:854652041398
17:55:56.976 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_MOTION, pointerId:0, currentPosition:[275, 92], timestamp:854652059739
17:55:56.977 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerMoved [Grid-00B6333C]
17:55:56.978 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Ignoring captures] raising event Enter (args: 00075A21) to original source [Grid-00B6333C]
17:55:56.979 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 00075A21) to original source first [Grid-00B6333C]
17:55:56.982 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 00075A21) to capture target [Grid-00B6333C] (-- no bubbling--)
17:55:56.983 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerMoved [Grid-00B6333C]
17:55:56.984 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Ignoring captures] raising event Enter (args: 011006D1) to original source [Grid-00B6333C]
17:55:56.985 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 011006D1) to original source first [Grid-00B6333C]
17:55:56.986 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Move (args: 011006D1) to capture target [Grid-00B6333C] (-- no bubbling--)
17:55:57.012 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_UP, pointerId:0, currentPosition:[275, 92], timestamp:854652096382
17:55:57.022 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerReleased [Grid-00B6333C]
17:55:57.023 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Released (args: 0350FC3A) to original source first [Grid-00B6333C]
17:55:57.024 VRB [DMXCore.DMXCore100.Views.MenuPage] Tap on card Host/Protocol
17:55:57.024 VRB [DMXCore.DMXCore100.Services.MenuFocusManager] Short press on item ListViewItem. Ctx.Count = 1, id Host/Protocol
17:55:57.026 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] [Implicit capture] raising event Released (args: 0350FC3A) to capture target [Grid-00B6333C] (-- no bubbling--)
17:55:57.163 DBG [Uno.UI.Xaml.Input.FocusRectManager] Hiding focus rect
17:55:57.165 DBG [Uno.UI.Xaml.Core.PointerCapture] ScrollContentPresenter-00E6CEC1: Releasing (Any) capture of pointer Touch/0
17:55:57.167 DBG [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ReleasePointerCapture not supported on Skia for FrameBuffer.
17:55:57.181 DBG [Uno.UI.Xaml.Input.FocusRectManager] Hiding focus rect

[dr1rrb]

Looking at the trace, it appears that when the "tap" event is not raised, the "pressed" is actually not dispatched properly:

17:55:52.085 VRB [Uno.UI.Xaml.Core.InputManager+PointerManager] PointerPressed [Grid-00B6333C]
    >>>>> NO TRACE OF DISPATCH HERE !!!!! <<<<<
17:55:52.086 VRB [Uno.UI.Runtime.Skia.FrameBufferPointerInputSource] ProcessTouchEvent: LIBINPUT_EVENT_TOUCH_MOTION, pointerId:0, currentPosition:[257, 88], timestamp:854647170526

(While we do have such trace when it works e.g. [Ignoring captures] raising event Pressed)

My first hypothesis would be that we have an exception between line 256 and line 260 in the PointerManager (as the first line of the Raise invoked at line 261 do trace some text) ... but if so it would just crash the app / stop input processing at it would abort the Thread that process them.

Any idea @jeromelaban ?

[HakanL]

Any update on this? Do you think it will work better if I run under Wayland/GTK (sizeable investment to move to that for me)? This is currently a showstopper for me, the touch interface is close to useless in Framebuffer on RPi :(

[jeromelaban]

There's no update on this topic, but indeed @dr1rrb, an unhandled exception in the processing of events would stop the thread completely.

@HakanL once your issue happens, pointers don't work at all?

[HakanL]

@jeromelaban No, it doesn't stop pointers, it just misses the tap. I have logging on unhandled exceptions/tasks as well. If I keep tapping then it will take the 2nd or 3rd time I tap. It seems to happen more on large buttons than smaller ones, but it's just a feeling, I haven't done a reliable testing on that. Could the transition animations exaggerate the issue?