port is slow to respond, please be patient

Project:Linux hardware
Component:Documentation
Category:support request
Priority:normal
Assigned:Unassigned
Status:active
Project wiki:Hardware
Related pages:#44: Hard drives and storage media
Description

Booting the computer is very slow.

There are error messages like:

ata2: port is slow to respond, please be patient

Is a drive failing?
How to investigate what causes it?