Arch Linux

xdyz5mx6

Member

Registered: 2018-08-27

Posts: 3

Touchpad not working since 4.18.3

Hi guys,

I'm using Arch Linux now for about half a year and it is working like a charm. Seems like I found my distro of choice.
Last week I updated the system and the kernel got updated from 4.17.14 to 4.18.3.
After the next reboot the touchpad of my Lenovo ThinkPad L470 (lsusb defines it as 'Synaptics...') stopped working.

Under the 4.17.14 kernel it worked like it should. Now only 'lsusb' shows the device, 'xinput list' does not anymore.
After manully downgrading the kernel to the previous one, the touchpad works again. So I guess it has to do with the newer kernel.

But now I really dont know where to start with finding a solution for that. I read about compiling a custom kernel or write a dkms module,
but that stuff is brand new to me, so I dont know where to start or even debug the error.

Thanks for ur help

Last edited by xdyz5mx6 (2018-08-28 18:07:04)

xdyz5mx6

Member

Registered: 2018-08-27

Posts: 3

Re: Touchpad not working since 4.18.3

Update 4.19.1

Still not working.

progandy

Member

Registered: 2012-05-17

Posts: 5,190

Re: Touchpad not working since 4.18.3

Hmm, can you try to set the kernel parameter psmouse.synaptics_intertouch to either 0 or 1? Maybe one of the two values will resurrect your device.
https://wiki.archlinux.org/index.php/Kernel_parameters

psmouse.synaptics_intertouch=0

psmouse.synaptics_intertouch=1

As for finding the git commit that introduced the bug, that is done by bisection. First check if 4.18 has the bug. If 4.18 is buggy, then bisect between 4.17 and 4.18. If v4.18 is working, then bisect between v4.18 and v4.18.3. If you use the linux-git package to bisect between versions of one stable release (v4.18.y), then you'll have to change the git source from

git+https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux

to

git+https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux.git

https://wiki.archlinux.org/index.php/Bi … s_with_Git

https://bbs.archlinux.org/viewtopic.php?id=234807

Last edited by progandy (2018-11-14 21:02:18)

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xdyz5mx6

Member

Registered: 2018-08-27

Posts: 3

Re: Touchpad not working since 4.18.3

Hmm, can you try to set the kernel parameter psmouse.synaptics_intertouch to either 0 or 1? Maybe one of the two values will resurrect your device.
https://wiki.archlinux.org/index.php/Kernel_parameters

psmouse.synaptics_intertouch=0

psmouse.synaptics_intertouch=1

Neither 0 nor 1 did the trick.

I already tried every kernel in the repos.
4.17.14 is the latest kernel that is working.
4.18.1 (the next available kernel) or newer is not.

ATM I dont have to the time to get into bisection stuff.
But it seems as it is the only option I got left to fix this bug.