I have a 3 year-old Samsung laptop with an AMD chipset, and I have never been able to get it to "sleep" properly under any Linux distro I have tried - and I have tried quite a few over the years. It would go to sleep, but it would not wake up; I would need to do a hard reset to get it working again.
It was a minor annoyance, and I never really figured out the cause. My laptop would sleep with Windows, and other laptops sleep fine under Linux, but not mine. I just got into the habit of powering down when I was done for the moment, and I as I had since upgraded to as SSD drive, boot time was about 10 seconds so no big deal.
About a month ago, I closed my laptop without thinking and when I opened it up again and pushed the power button...it woke up, I logged on and away I went. It has done so without any drama since. I have been using Elementary OS for a while (very pleasant to use, by the way), but it had originally exhibited the "no sleep" behavior too. I can only assume a kernel update or something quietly took care of the issue.
Everything comes to those who wait, I guess...