Re: USB drivers

From: Chris <chris_at_tellme3times.com>
Date: Sun, 08 Aug 2004 00:08:22 -0400
Darren Pilgrim wrote:

>>From: M. Warner Losh
>>
>>In message: <41124C8B.2060902_at_tellme3times.com>
>>            Chris <chris_at_tellme3times.com> writes:
>>: 
>>: What I am trying to determine is why my multifunction
>>    
>>
>printer/scanner 
>  
>
>>: receives only one of the two  drivers. Is it because the printer
>>    
>>
>does 
>  
>
>>: not respond properly? Is it because the printer is not defined? I
>>: have many questions here.
>>
>>Yes.  Usb is a little complicated in this area, and there are a number
>>of details that are hard to get right.  It wouldn't surprise me if the
>>current set of drivers are less than completely optimal.
>>    
>>
>
>On a bit of a side-track, I'm wondering if it could be due to how the
>multifunction device presents itself?  A bit back in this thread someone
>mentioned that a pointer must be present for a driver to attach to a
>device.  If there is only one pointer for a device, only one driver may
>attach.  Since a single USB bus can have a LOT of devices and each
>device's capabilities are determined through the presence of usage
>pages, I see two ways for a multifunction device to present itself:
>
>- A single device ID with more than one usage page.  All the
>functionality is there and is compatible with FreeBSD drivers, but since
>there is only one device probed on the bus, only one driver may attach.
>Perhaps a "simple" mux driver would be useful?
>
>- A multiple single-usage device IDs.  Same functionality as before, but
>now FreeBSD can probe unique printer and scanner devices and thus let
>both ulpt and uscanner attach simutaneously.
>
>Am I way off base?
>
>
>  
>
What I would like to know is where are these tests done. Or should I say 
where does USB start to load and what are the steps in between.

Chris
Received on Sun Aug 08 2004 - 02:01:52 UTC

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