Hello, I'm having the same issue with suspend mode, as OP described. I have an IdeaPad Slim also. I tried the above steps of editing grub, and no luck. The keyboard does wake the laptop, but you cannot type your password. I dont see any way to "wake" the keys up, either.
You could try this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash 'i8042.debug=1' 'i8042.nopnp' 'i8042.noloop'"
When you test the different kernel parameters, don't forget to run sudo update-grub afterwards and reboot to test. If it doesn't help, remove the added terms.
Which Ideapad slim do you have?
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That worked! I see that I was neglecting to include the ' ' (single quotes) surrounding the parameters, in my previous attempts editing grub. Thank you so much!!! Now I can re-enable lid close suspend again. 
Edit: BTW I have an IdeaPad Slim 3 15AHP10. That might help someone in the future.
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Glad to hear that it works now! I think the single quotes are not needed, but I found this solution in a reddit post and copied it as it was.
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