2005-02-03 00:24:33

by Aleksey Gorelov

[permalink] [raw]
Subject:

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.


2005-02-03 01:14:07

by Matthew Dharm

[permalink] [raw]
Subject: Re: your mail

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: [email protected]
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


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2005-02-03 16:03:58

by Alan Stern

[permalink] [raw]
Subject: Re: your mail

On Wed, 2 Feb 2005, 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.

Lots of devices don't need that delay, but enough of them do that we
decided to add it. The value of 5 seconds was more or less arbitrary; it
was long enough for every device we could test and it didn't seem _too_
long. Maybe 1 second would be long enough -- we just didn't know so we
were conservative.

Alan Stern