My loss of the touchscreen seems to be due to my doing a lot of experimenting with evtest and udev's hwdb. After an S3 resume this morning the touchscreen Synaptic devices re-appeared. Thinking about it, it may also be due to some ACPI DSDT experimentation I was doing to try to get the Fn+F5-F7 backlight brightness control to operate.
My loss of the touchscreen seems to be due to my doing a lot of experimenting with evtest and udev's hwdb. After an S3 resume this morning the touchscreen Synaptic devices re-appeared. Thinking about it, it may also be due to some ACPI DSDT experimentation I was doing to try to get the Fn+F5-F7 backlight brightness control to operate.