Re: Make USB/SCSI delay to avoid timeouts?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Jan 13, 2014 at 12:59:34AM +0000, Thomas Mueller wrote:
> from my original post:
> 
> > Is there a way to enforce a delay in probing USB or SCSI in NetBSD, to 
> > possibly avert timeouts/disconnects?
> 
> > In FreeBSD, there is a tunable loader parameter.
> 
> > In /boot/defaults/loader.conf, there is a line showing the default (FreeBSD)
> 
> > #kern.cam.scsi_delay="2000"     # Delay (in ms) before probing SCSI
> 
> > Not many computer users actually have SCSI these days, but USB uses SCSI 
> > subsystem.
> 
> > This 2000 milliseconds can be set higher, like 13000, and has helped me in 
> > FreeBSD.
> 
> > How can I achieve this effect in NetBSD?
> 
> Manuel Bouyer responded:
> 
> > A better question would be: why is 2s not enough ?
> 
> How is that for an evasive answer?

Your question was not very precise too. There's multiple timeouts in the
scsi and usb stacks, I don't know which one you're talking about.

> 
> Or is this a devious way of saying I should stick with FreeBSD and Linux?
> 
> There tends to be a little delay in recognizing a USB device, and keeping it 
> up.
> 
> I notice that setting kern.cam.scsi.delay="13000" or whatever it is now seems 
> to prevent device timeouts on the Hiro H50191 wi-fi adapter in FreeBSD.

So the problem is with a wifi adapter. It has nothing to do with SCSI.

Now we should find why this device needs more than 2s to show up
(i.e. which timeout needs to be raised).
This way it will work would of the box, without tuning anything.

You could start with turning on USB debugs (options USB_DEBUG in kernel
config file), and set usbdebug to 0xffff in usb.c.
Alternatively you can set usbdebug from ddb (w usbdebug 0xffff)
just before pluggin in the device.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--