Date: Tue, 06 Jun 2006 20:13:25 +0800 From: mag@intron.ac To: "Julian Stacey" <jhs@berklix.org> Cc: garyj@jennejohn.org, freebsd-usb@freebsd.org Subject: Re: usbdevs "self powered" is misleading Message-ID: <20060606133612.B981EF16EC@smtp.263.net> In-Reply-To: <200606051201.k55C1NHd087760@fire.jhs.private> References: <200606051201.k55C1NHd087760@fire.jhs.private>
next in thread | previous in thread | raw e-mail | index | archive | help
Power supply current required by USB device is reported by USB
device itself. If you consider the "self powered" to be incorrect,
the fault should be owed to the USB device.
------------------------------------------------------------------------
From Beijing, China
Julian Stacey wrote:
> "self powered" is reported by 6.1-RELEASE usbdevs for my small external disc.
> It seems a misnomer & should at most be "Can be self powered" ?
> The disc housing has a socket to apply power, but was not plugged
> in. (I don't even have a power supply for it). Disc was cabled
> direct to laptop, not through a hub, & showed:
> Controller /dev/usb1:
> addr 1: full speed, self powered, config 1, UHCI root hub(0x0000),
> Intel(0x0000), rev 1.00
> port 1 addr 2: full speed, self powered, config 1,
> USB 2.0 Storage Device(0x5621), vendor 0x0402(0x0402), rev 1.03
> When I added a USB-2 Hub (with hub power supply plugged in to 220V)"
> Controller /dev/usb1:
> addr 1: full speed, self powered, config 1, UHCI root hub(0x0000),
> Intel(0x0000), rev 1.00
> port 1 addr 2: full speed, self powered, config 1,
> USB2.0 Hub Cont(0x0058), NEC Corporation(0x0409), rev 1.00
> port 1 addr 5: full speed, self powered, config 1,
> USB 2.0 Storage Device(0x5621), vendor 0x0402(0x0402), rev 1.03
> Sometimes "self powered" seems correct though, as for eg:
> - a GPS with battery inside.
> - a USB2-IDE + 3.5" IDE disc + external 220V supply
> Comments ?
>
> Julian
> --
> Julian Stacey. Internet & Unix Consultant, Munich. http://berklix.com
> Mail in Ascii, HTML = spam. Ihr Rauch = mein allergischer Kopfschmerz.
> _______________________________________________
> freebsd-usb@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-usb
> To unsubscribe, send any mail to "freebsd-usb-unsubscribe@freebsd.org"
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060606133612.B981EF16EC>