Intermittent touchpad lag on Dell XPS 9510
Summary
The touchpad on Dell's new XPS 9510 is intermittently laggy and inaccurate. The problem does not occur on Windows or with the legacy synaptics driver. While in the bad state, the cursor moves more slowly and it's much more difficult to make precise movements.
Steps to reproduce
Use Fedora 34 on a Dell XPS 9510 for approximately 10 minutes, by which time the problem is likely to occur. The problem usually occurs for a few minutes at a time. (Otherwise, the touchpad is perfectly responsive.)
Required information
- libinput version: libinput-1.18.0-2.fc34.x86_64
- hardware information: Dell XPS 9510 with Elan trackpad 04F3:311C
-
libinput record
output: record-good.yml record-bad.yml -
libinput debug-events --verbose
output: debug-good.log debug-bad.log
$ udevadm info /sys/class/input/event4
P: /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-DLL0945:00/0018:04F3:311C.0001/input/input13/event4
N: input/event4
L: 0
S: input/by-path/pci-0000:00:15.1-platform-i2c_designware.1-event-mouse
E: DEVPATH=/devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-DLL0945:00/0018:04F3:311C.0001/input/input13/event4
E: DEVNAME=/dev/input/event4
E: MAJOR=13
E: MINOR=68
E: SUBSYSTEM=input
E: USEC_INITIALIZED=22492332
E: ID_INPUT=1
E: ID_INPUT_TOUCHPAD=1
E: ID_INPUT_WIDTH_MM=150
E: ID_INPUT_HEIGHT_MM=88
E: ID_SERIAL=noserial
E: ID_PATH=pci-0000:00:15.1-platform-i2c_designware.1
E: ID_PATH_TAG=pci-0000_00_15_1-platform-i2c_designware_1
E: LIBINPUT_DEVICE_GROUP=18/4f3/311c:i2c-DLL0945:00
E: DEVLINKS=/dev/input/by-path/pci-0000:00:15.1-platform-i2c_designware.1-event-mouse
$ xinput list-props 16
Device 'DLL0945:00 04F3:311C Touchpad':
Device Enabled (201): 1
Coordinate Transformation Matrix (203): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Tapping Enabled (335): 1
libinput Tapping Enabled Default (336): 0
libinput Tapping Drag Enabled (337): 1
libinput Tapping Drag Enabled Default (338): 1
libinput Tapping Drag Lock Enabled (339): 0
libinput Tapping Drag Lock Enabled Default (340): 0
libinput Tapping Button Mapping Enabled (341): 1, 0
libinput Tapping Button Mapping Default (342): 1, 0
libinput Natural Scrolling Enabled (343): 1
libinput Natural Scrolling Enabled Default (344): 0
libinput Disable While Typing Enabled (370): 1
libinput Disable While Typing Enabled Default (371): 1
libinput Scroll Methods Available (345): 1, 1, 0
libinput Scroll Method Enabled (346): 1, 0, 0
libinput Scroll Method Enabled Default (347): 1, 0, 0
libinput Click Methods Available (348): 1, 1
libinput Click Method Enabled (349): 0, 1
libinput Click Method Enabled Default (350): 1, 0
libinput Middle Emulation Enabled (351): 0
libinput Middle Emulation Enabled Default (352): 0
libinput Accel Speed (353): 0.272059
libinput Accel Speed Default (354): 0.000000
libinput Accel Profiles Available (355): 1, 1
libinput Accel Profile Enabled (356): 1, 0
libinput Accel Profile Enabled Default (357): 1, 0
libinput Left Handed Enabled (358): 0
libinput Left Handed Enabled Default (359): 0
libinput Send Events Modes Available (320): 1, 1
libinput Send Events Mode Enabled (321): 0, 0
libinput Send Events Mode Enabled Default (322): 0, 0
Device Node (323): "/dev/input/event4"
Device Product ID (324): 1267, 12572
libinput Drag Lock Buttons (360): <no items>
libinput Horizontal Scroll Enabled (361): 1
$ cat /sys/class/dmi/id/modalias
dmi:bvnDellInc.:bvr1.3.2:bd06/17/2021:br1.3:svnDellInc.:pnXPS159510:pvr:rvnDellInc.:rn0C6CP1:rvrA00:cvnDellInc.:ct10:cvr: