It's basically just like the code says.

A lot of devices choke if you access them too quickly after enumeration.
The 5 second delay seems to be enough for most devices.  But we made it
adjustable exactly for people like you.

Matt

On Wed, Feb 02, 2005 at 04:17:13PM -0800, Aleksey Gorelov wrote:
> Hi Matt, Alan, 
> 
>   Could you please tell me (link would do) why it makes default
> delay_use=5 
> really necessary (from the patch below)?
> https://lists.one-eyed-alien.net/pipermail/usb-storage/2004-August/00074
> 7.html
> 
> It makes USB boot really painfull and slow :(
> 
>   I understand there should be a good reason for it. I've tried to find
> an answer in 
> archives, without much success though.
> 
> Thanks,
> Aleks.

-- 
Matthew Dharm                              Home: mdharm-usb@one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

Now payink attention, please.  This is mouse.  Click-click. Easy to 
use, da? Now you try...
					-- Pitr to Miranda
User Friendly, 10/11/1998