"Password incorrect" after wakeup from suspend

[Jazz]

Everytime I suspend my vanilla Ubuntu 15.10 (upgraded from clean 15.04) I have the same issue: the login screen after I wake up my laptop says my password is incorrect, which is not true. I use two keyboard layouts (Croatian and English) and don't use any special characters, so I chose a simple password for this - all of the letters are at the same place on both of those keyboard layouts!

The background image on the login screen is also not loaded completely after the computer was suspended - it loads only 50% or so, and the rest of the image is filled with grey.

I tried to switch to both of my keyboard layouts and the same message appears: Incorrect password, please try again.

Then I tried to suspend it again from the menu at the upper-right corner, but it refuses to suspend from there. Each time I have to manually turn off my laptop by pressing and holding the power-off button. After the same login screen appears, (but this time it's NOT after the laptop was suspended) I have no problems to login.

It's also not a caps lock issue with my password. And when I don't suspend my laptop, open tty1, I could login normally.

[Jazz (iguanamiyagi)]

I've noticed couple of similar reports for some older releases, but none of the proposed solutions worked for me:
http://askubuntu.com/questions/459720/14-04-password-not-accepted-after-computer-wakes-up-from-sleep

I did not have such issues with 15.04.

$ sudo lshw -c video
  *-display
       description: VGA compatible controller
       product: Seymour [Radeon HD 6400M/7400M Series]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 0
       bus info: pci@0000:01:00.0
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
       configuration: driver=radeon latency=0
       resources: irq:32 memory:c0000000-c7ffffff memory:cc400000-cc41ffff ioport:3000(size=256) memory:cc440000-cc45ffff

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1551115/+editstatus and add the package name in the text box next to the word Package.

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