"Have you checked it's plugged in?" Fixing the touchpad after an Ubuntu update (by turning it on)
After the last Ubuntu update (the last before today’s), I suddenly lost my touchpad. It worked during boot, but not after log in.
I did the usual searching around for people with similar problems (and it seems to be something that comes up, going back years—which can be a problem, since Ubuntu has gone through some pretty fundamental changes in how it handles devices over the last few years). I followed the advice at the Ubuntu debugging page. Running cat /proc/bus/input/devices
showed that there was a touchpad being detected (though not a synaptics touchpad as all the examples seem to be):
I: Bus=0018 Vendor=06cb Product=76af Version=0100
N: Name="DELL07E6:00 06CB:76AF Touchpad"
P: Phys=i2c-DELL07E6:00
S: Sysfs=/devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-1/i2c-DELL07E6:00/0018:06CB:76AF.0001/input/input12
U: Uniq=
H: Handlers=mouse0 event9
B: PROP=5
B: EV=1b
B: KEY=e520 10000 0 0 0 0
B: ABS=260800000000003
B: MSC=20
On that page I read that some times the trouble is that the touchpad is being detected as a mouse and so isn’t working well for that reason. So I decided to see how it was being reported in “settings.”
And that was the answer Settings>Devices>Mouse & Touchpad showed that the touchpad was turned off. Not something I did (or at least not something I remember doing), but an easy solution.