Thanks for your useful comments!
So, I guess the first thing to try is getting an external powered USB hub,
and try it again (presuming that it delivers at least 5 V).
regards
wim
> Greg K-H wrote:
>
>> On Wed, Jan 21, 2009 at 09:30:59PM +0100, Wim de Vries wrote:
>> > OK. Thanks.
>> > I have measured the voltage, with the device connected:
>> > on my (Win) PC 5.10 V
>> > on my (Linux) laptop: 5.12V
>> > on the asus eee pc: 4.96V
>> > Do you think that difference is a problem?
>>
>> Yes, that is on the lower bound of what the device is expecting, so it
>> could cause problems.
>
> 4.96 V would appear to be well within the bounds of the specification.
> USB2.0 paragraph 7.2.2 (page 175) says:
>
> * The voltage supplied by high-powered hub ports is 4.75 V to 5.25 V.
> * The voltage supplied by low-powered hub ports is 4.4 V to 5.25 V.
>
> There is a diagram, Figure 7-47, on the same page, which details the
> allowable voltages at various points in the USB power distribution
> system.
>
> Dave
>
>
> NICE CTI Systems UK Limited ("NICE") is registered in England under
> company number, 3403044. The registered office of NICE is at Tollbar Way,
> Hedge End, Southampton, Hampshire SO30 2ZP.
>
> Confidentiality: This communication and any attachments are intended for
> the above-named persons only and may be confidential and/or legally
> privileged. Any opinions expressed in this communication are not
> necessarily those of NICE. If this communication has come to you in error
> you must take no action based on it, nor must you copy or show it to
> anyone; please delete/destroy and inform the sender by e-mail immediately.
>
> Monitoring: NICE may monitor incoming and outgoing e-mails.
>
> Viruses: Although we have taken steps toward ensuring that this e-mail and
> attachments are free from any virus, we advise that in keeping with good
> computing practice the recipient should ensure they are actually virus
> free.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
