USB drivers
Chris
chris at tellme3times.com
Sat Aug 7 21:01:52 PDT 2004
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
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