Sometimes keyboard and mouse do not respond at KDE login window in Ubuntu 14.04

If you make a fresh Ubuntu user and log in as that, is it ok?

No. The problem is that I cannot type the password in the login screen,
because the keyboard doesn't work. I don't see the mouse pointer either.

if you unplug it and plug it back in, is it ok?
Have you tried a different keyboard to test?

> if you unplug it and plug it back in, is it ok?

No

> Have you tried a different keyboard to test?

I have just tried it. It fails sometimes, but much less than with the other keyboard.

I'm having the same problem also with an Inspiron 3847 bought just last week.

The first time the keyboard and mouse did not work happened straight after installing 14.04 after the first boot up.

For the last two mornings on powering up the computer the keyboard and mouse did not work again. Rebooting once was enough to get them working. This is with the lastest updates having done a dist-upgrade.

I've read elsewhere that this issue is kernel related. FWIW I'm running 3.13.0-46-generic #75-Ubuntu SMP

Something else worth noting is that while the mouse and keyboard are not working, I can connect remotely through ssh.

Jeremy: Does it happen to you with the original keyboard from Dell or with another keyboard?
I have more problems with the original one.

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Sorry Herrero - I didn't see your reply until now.

Yesterday I did a dist-upgrade which included a kernel update and it made the situation worse. On every startup the mouse and keyboard didn't work. I swapped both mouse and keyboard but still had the issue.

I then realised that I was running kernel 3.13 and that the latest 14.02 includes 3.16. Updating to kernel 3.16 appears to have fixed the issue. After 3 reboots so far the keyboard and mouse have worked every time.

Thank you for the information, I will update the kernel

It works!!! Thank you so much, Jeremy!!!