Q:

Ubuntu 16.04 - cannot enter password at disk decryption splash screen

I've researched far and wide on why I can't enter the disk decryption password at boot up, and though I've found some other similar questions to mine, I haven't found any solutions.  It seems others who have experienced this have either solved it without responding how, or they've just given up. 
I have both a disk decryption password and a desktop unlock password to enter with every boot.  I originally installed Ubuntu 14.04, and after several OS updates, things started to act buggy (my display started to get screwed up, etc) and I eventually caved on Ubuntu's incessant reminders of upgrading to 16.04. 
Once that was done, only some of my display issues were "healed" (still some bugs upon boot up), but the biggest issue is now my disk decryption splash screen will not take a password.  I used to be able to enter a password and see the dots enter in the text field for the password, but I can't get anything to type there now. 
I have to either hard reboot the system by holding down the power button, or holding CTRL+ALT+DELETE to knock me back to the GRUB boot screen where I will eventually get to a simple console (black background with white console font) where I'm prompted for my decryption password and I can successfully unlock the disk. ( I should also mention that at this point, there are two errors displayed: 1) TPM error, cannot read pcr value 2) Something about not being able to find/read "ubuntu-vg".) 
Like I say, this may seem like a duplicate of others on here, but their problems either weren't exactly the same as mine, or the solutions they were given didn't work. 
I kinda don't want to just have it default to "nosplash" (which didn't work when I edited the grub file).  I really want the install to run as intended! 
I've heard there was v16.10 coming out that's supposed to fix some of these issues, but I haven't found the update - nor do I know if it will fix this. 
This is the disk unlock splash screen (NOTE: This used to show dots for each character typed.  Now it doesn't respond to keyboard actions and it does not record a password when typed, even without the echo). 

If I press CTRL+ALT+DEL, I am taken to the GRUB screen where I select "Ubuntu" to boot normally. 

When I select "Ubuntu" to boot normally, I am presented with the following errors and a prompt to enter the disk decrypt password (which now works).  The TPM error is followed by "unable to read pcr value". 

A:

I had the same issue after installing proprietary NVIDIA GPU driver.  Disabling splash screen worked for me.  I know this is not a complete solution, but I think this workaround might be helpful because it is better than using GRUB menu options on every system boot. 
I edited /etc/default/grub file: removed quiet splash from the GRUB_CMDLINE_LINUX_DEFAULT parameter.  Then run sudo update-grub.  Now the splash screen is gone and and I see a prompt to enter disk encryption as on the last screenshot in the question. 
I am running Ubuntu 17.04, Linux kernel 4.10, NVIDIA driver 375.39.