Status of high-speed usb drivers

Davon Shire davon at
Tue Oct 19 04:15:04 PDT 2004

Dick Davies wrote:

>* Davon Shire <davon at> [1055 16:55]:
>>Dick Davies wrote:
>>>It's already in. man 4 ehci.
>>*BUGS* <#end> The driver is not finished and is quite buggy. Currently 
there is no support for hubs that are connected with high speed upstream 
and low or full speed downstream (i.e., for transaction transla- tors). 
There is also no support for interrupt or isochronous transfers.
>>Mr Davies,
>> Thank you for the informative reply however this doesn't answer my
>>question. Yes there is a ehci driver but as you can read. there is no 
High-Speed support.
>If by high-speed support you mean 'as fast as a local disk' then try it. It
>> While I appreciate the quick reply. Reading my messages in detail
>>might have been a little more enlightening in the kind of info I wanted.
>It would have taken you lees time to type 'kldload ehci'
>than to write a sarcastic email.
No sarcasm. Just a straight reply.

Mr Davies,
  I have already and on several dozen occassions loaded the ehci module.
I know how to load, unload, reload, Pre-load modules. I am very good at 
running FreeBSD. I want to use the high-speed ability of usb 2.0 this is  on
the spec order of 480 Mb/s. I can get 16 - 25 MB/s using Linux or  Windows
(Sustained). Freebsd I've never had more than 1 MB/s unless I'm  using dd to
dump from the raw partition to /dev/null and then I get 2.2MB/s
  If you can get the proper kind of thruput from devices using the ehci
driver. Please tell me what you did it with and how you did it.

Thankyou. Davon Shire.

  For clarity to all interested. USB in it's current state has 3
transfer speeds in general use. slow, full and high, speed.
  Slow: is quite low about 1.2 Mbits / s if I remember correctly.
Generally used for low input rate things like mice and keyboards.
  Full: is  spec'd at 12.0 Mbits/s This is in line with USB 1.1 and is
generally used by higher speed devices but with of course limited  bandwidth.
Most USB web camera's use this which accounts for their lousy  frame rate.
High: is spec'd at 480 Mbits/s this is why USB 2.0 is so important. It 
technically can be faster than firewire for data transfer. Specially  between
Usb Hard drives and computers etc. There are highspeed USB  camera's that can
provide very high frame rates, of course burning or  playing DVD's is really
impractical unless you use something like USB  2.0 etc. As USB 1.1 does not
have the bandwidth.

Drivers associated with various USB interfaces are:
ohci (older but still used usb 1.0/1.1) chips
uhci (Current versions of USB 1.1) interfaces.
ehci (current versions of USB 2.0) interfaces.

Mind you these provide a uniform communication conduit for other drivers  that
help you talk to specific devices. such as usb eithernet adaptors,  AUE, Data
devices like hard drives. UMASS and mouses UMS.

Again thank you for your time.

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