USB Speed Checking

John Tapsell johnflux at gmail.com
Tue Jul 29 08:00:49 PDT 2008


2008/7/29 Martin Owens <doctormo at gmail.com>:
> Thanks for the feedback guys...

Martin,

  That's pretty damn cool.

  I can have a go at adding KDE support for this when this is added
HAL and you are happy with it.

John Tapsell

>
>> Bastien Nocera Wrote:
>> You're not checking whether the device that's being plugged in is a USB 2 device though...
>
> Did you read the code? I thought I was. I thought I'd even written it
> to support usb3.
>
>> David Zeuthen Wrote:
>
>  - Should cover more than just mass storage devices.
>
> It does.
>
>> What happens at session startup? The right thing is probably to
>> create a small notification icon but no bubbles (bubbles at login is normally frowned upon)
>
> Nothing, you have to manually start the proof of concept code to get
> the notify event.
>
>> Bonus points for telling the user what ports (ideally mention the hub by name)
>> he can plug his Hi-Speed device into instead.
>
> Hub name is just the parent devices name, the list of possible usb
> ports would be more interesting problem.
>
>> What is the user interaction like? I'd suppose the right thing is to create an icon and show a notification bubble.
>> You probably also need some button for the user "Stop" (e.g. unmount
>> or other actions) the device before the user yanks it out to plug it into another port.
>
> That's really for the implementation, the libnotify daemon is a proof
> of concept to show if it can be done.
>
>>  How do you determine if a Hi-Speed device isn't running at full speed? IIRC it's non-trivial to do it right (you'd have
>>  to look at some of the device descriptors not exposed in sysfs) and pretty easy to do it wrong.
>
> So far I'm only able to detect if the device runs at less than the max
> speed of the version it has available. If you know a better way and
> cause show me the example case I could try and fix it.
>
>> Btw, here are some old screen shots on how this works on Windows XP. It
>> might be useful to try and solve the "power exceeded" problem too.
>
> That shouldn't be difficult either, if the usb device requires 50mh of
> power and the usb hub is either unpowered (and routing the 500mh from
> the computer) or somehow unpowered completely (not sure if that's
> possible) or the power requirements are greater than the max power of
> the hub.
>
> Best Regards, Martin Owens
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