My girlfriend has a laptop where I recently installed Ubuntu (dual boot with Windows). The keyboard works at the grub menu screen, but when the system starts, sometimes it takes more than a minute for the keyboard to become responsive. Meanwhile, the trackpad works just fine. Sometimes it takes as little as 4 seconds (this is when the keyboard seems to work immediately), other times it's way over 40s (this is when the keyboard feels like it takes a long time for it to work).
What could be the cause of the delay? It's a laptop, so I cannot change the keyboard.