Touchpad doesn’t work after suspend in Ubuntu 16.04 for Yoga900

发现Yoga900每次关闭盖子后再打开触摸板都失控, 需要使用触屏来操作. 探索了一天终于找到一个可用的解决方法了. 貌似网上没有正式的解法, 或者等ubuntu更新吧.

1. Know you Touchpad ID

Run xinput list to find the device for pointer and keyboard. We only pay attention to the Virtual core pointer part.

hom@Yoga900:~$ xinput list
⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳ ELAN21EF:00 04F3:21EF                   	id=11	[slave  pointer  (2)]
⎜   ↳ SYNA2B29:00 06CB:77C6                   	id=10	[slave  pointer  (2)]
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Power Button                            	id=6	[slave  keyboard (3)]
    ↳ Video Bus                               	id=7	[slave  keyboard (3)]
    ↳ Power Button                            	id=8	[slave  keyboard (3)]
    ↳ Lenovo EasyCamera                       	id=9	[slave  keyboard (3)]
    ↳ Ideapad extra buttons                   	id=12	[slave  keyboard (3)]
    ↳ AT Translated Set 2 keyboard            	id=13	[slave  keyboard (3)]

Here, the ELAN device is the touchscreen and SYNA device is the touchpad for my Yoga900. The ID for touchpad is 10 here.

To make sure the unknown name for your device, you can try xinput disable ID to disable and then test it. Then xinput enable ID to recover it.

The id may be catch by command tp_id=`xinput list | grep -i touchpad | awk '{ print $5 }' | sed 's/id=//'` (Here SYNA instead of “touchpad”). If the device id will change, the following device id can be replaced by `xinput list | grep -i touchpad | awk '{ print $5 }' | sed 's/id=//'`

2. Create a executable script to reset touchpad after resume from suspend

This step to fix the problem when using pm-suspend command to suspend. Indeed, when computer pm suspend/resume, it will run the commands in the case part.

xinput disable diviceID; xinput enable diviceID is the command to restart the device. Other commands as:

• xinput set-prop 10 "Device Enabled" 0; xinput set-prop 10 "Device Enabled" 1 is the same. the device ID can also be the name as “SynPS/2 Synaptics Touchpad”. This method can also set other properties!~
• sudo synclient TouchpadOff=1; sudo synclient TouchpadOff=0; can restart when normally in ubuntu, but failed when resume from suspend.
• Some places say: modprobe -r psmouse; modprobe psmouse;. Or using rmmod instead modprobe -r. I tried, but nothing happen…

To create a script (The name can as you like~) at pm-sleep.d folder:

sudo gedit /etc/pm/sleep.d/99_touchpad

Contents for /etc/pm/sleep.d/99_touchpad (Change the user name ‘hom’ to your user name! Also device id 10 here!):

#! /bin/bash

case $1 in
	# For suspend action
     suspend|suspend_hybrid|hibernate)
        DISPLAY=:0.0 su hom -c 'xinput disable 10'
        ;;
    # For resume action
     resume|thaw)
        DISPLAY=:0.0 su hom -c 'xinput list'
        DISPLAY=:0.0 su hom -c 'xinput disable 10'
        DISPLAY=:0.0 su hom -c 'xinput enable 10'
        ;;
esac

Become executable: sudo chmod +x /etc/pm/sleep.d/99_touchpad

Notice: to generate this script at /etc/pm/sleep.d/ folder can help to fix the same problem when run pm-suspend command. If you done above step, try to run pm-suspend to suspend your computer and then resume it. Can it work? No? Further check what’s wrong..

Use systemd service to hook for suspend

Generate the service configuration file as follow:

/etc/systemd/system/touchpad-resume.service :

[Unit]
Description=Local system resume actions for touchpad
After=suspend.target

[Service]
Type=simple
ExecStart=-/etc/pm/sleep.d/99_touchpad resume

[Install]
WantedBy=suspend.target

And then run sudo systemctl enable root-resume.service to enable the service, which will automatically generate /etc/systemd/system/suspend.target.wants/touchpad-resume.service file.

OK, now try to restart and close the lid~

Maybe sometimes will fail and resolution will change to too high.. At that time, try:
- press Ctrl+Alt+F1 then Ctrl+Alt+F7 to reload the X window. - Or press xinput disable 10; xinput enable 10 to restart it in command line. (Change to your device ID) - Or use graphic system setup~

附录: 尝试 The tries..

1. Touchpad doesn’t work after suspend 这篇介绍了使用/etc/pm/sleep.d/新建脚本处理的方法, 但测试并不行, 上面提到了, Ubuntu16并不是使用pm-suspend来睡眠的,而是systemd处理. 使用该方法后, 再用pm-suspend睡眠, 再恢复时是有效的. 但重开盖子或者在总菜单里点suspend按钮睡眠恢复都无效.
2. Laptop does not suspend when lid is closed: 这篇文章介绍使用acpi监控设备服务来监控设备关闭就执行pm-suspend. 经测试也无效, 出现现象是, 关闭盖子恢复后还会再执行一次suspend. 而两次都没有恢复触摸板. 所以我开始怀疑, ubuntu16使用另外的服务来监控和执行另一个suspend. 这篇文章也提到了修改/etc/systemd/logind.conf 可以更改关闭盖子时的行为(例如休眠或者关机). 其实就执行最后一个先创建/etc/acpi/events/lidbtn来设置监控盖子的服务, 然后执行相应脚本/etc/acpi/lidbtn.sh 就可以了, 脚本内容可以按照他grep设备状态的写法. /etc/acpi/里面的是监控设备的脚本, /proc/acpi/button/lid/LID0/state是设备(这里是盖)的状态.
3. Ubuntu 15.04 Suspend doesn’t run pm-suspend 最后关键就是要找到Ubuntu16究竟是用什么运行suspend, 直到看到这篇帖子的方法. 实际上Ubuntu15/16 使用systemd而不是upstart来执行suspend动作, 而其并不执行pm-utils. 所以上一次的测试失败了. 据此写了第三步.
4. how to execute a command after resume from suspend?: 这篇帖子介绍将脚本放在/lib/systemd/system-sleep/来执行, 经测试无效.

• Understanding Suspend by ACPI : 官方wiki关于电源管理
• pm-action