Re: Touchpad multitouch leaves ghost fingers
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From: Yinon Burgansky <hidden>
Date: 2025-09-23 21:56:38
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On Tue, Sep 23, 2025 at 7:30 PM Benjamin Tissoires [off-list ref] wrote:
Got something out with https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/204 that seems to solve your case on the hid-recorder you provided.
Thank you so much! The install command didn't work properly for me:
$ ./install.sh "*DLL0945*"
$ tree /usr/local/lib/firmware
/usr/local/lib/firmware
└── hid
└── bpf
└── 0011-Synaptics__DLL0945.bpf.o
$ reboot
$ sudo tree /sys/fs/bpf
/sys/fs/bpf
0 directories, 0 files
I tried to add it manually and it seems to work now :)
$ sudo udev-hid-bpf add /sys/bus/hid/devices/0018:06CB:CE26.0005
/usr/local/lib/firmware/hid/bpf/0011-Synaptics__DLL0945.bpf.o
$ sudo tree /sys/fs/bpf
/sys/fs/bpf
└── hid
└── 0018_06CB_CE26_0005
└── 0011-Synaptics__DLL0945_bpf
└── synaptics_dll0945
4 directories, 1 file
But I have to do it manually every time. Not sure what's wrong, maybe the added udev rule:
$ cat /etc/udev/rules.d/81-hid-bpf.rules
ACTION!="add|remove|bind", GOTO="hid_bpf_end"
SUBSYSTEM!="hid", GOTO="hid_bpf_end"
# We lookup the hwdb during bind to set the property, but we don't do
anything else
IMPORT{builtin}="hwdb --subsystem=hid --lookup-prefix=hid-bpf:"
#ACTION=="add", ENV{.HID_BPF}=="1",
RUN{program}+="@@BINDIR@@/udev-hid-bpf add $sys$devpath"
#MARKER
ACTION=="add", ENV{.HID_BPF}=="1",
RUN{program}+="/usr/local/bin/udev-hid-bpf add $sys$devpath"
#ACTION=="remove", ENV{.HID_BPF}=="1",
RUN{program}+="@@BINDIR@@/udev-hid-bpf remove $sys$devpath"
#MARKER
ACTION=="remove", ENV{.HID_BPF}=="1",
RUN{program}+="/usr/local/bin/udev-hid-bpf remove $sys$devpath"
LABEL="hid_bpf_end"
this is the udevadm info (after reboot, it is sometimes hidraw3 sometimes hidraw4):
$ udevadm info --query=all --name=/dev/hidraw4
P: /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-DLL0945:00/0018:06CB:CE26.0005/hidraw/hidraw4
M: hidraw4
R: 4
J: c242:4
U: hidraw
D: c 242:4
N: hidraw4
L: 0
E: DEVPATH=/devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-DLL0945:00/0018:06CB:CE26.0005/hidraw/hidraw4
E: DEVNAME=/dev/hidraw4
E: MAJOR=242
E: MINOR=4
E: SUBSYSTEM=hidraw
E: USEC_INITIALIZED=3980846
E: ID_VENDOR_FROM_DATABASE=Dell Inc
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: ID_FOR_SEAT=hidraw-pci-0000_00_15_1-platform-i2c_designware_1
E: TAGS=:seat:
E: CURRENT_TAGS=:seat:
Thank you for the quick fix, it seems to work great so far! Yinon