Date: Tue, 06 Jun 2006 23:46:33 +0200 From: "Julian H. Stacey" <jhs@flat.berklix.net> To: mag@intron.ac, "M. Warner Losh" <imp@bsdimp.com> Cc: garyj@jennejohn.org, freebsd-usb@freebsd.org Subject: Re: usbdevs "self powered" is misleading Message-ID: <200606062146.k56LkXvC019523@fire.jhs.private> In-Reply-To: Message from mag@intron.ac of "Tue, 06 Jun 2006 20:13:25 %2B0800." <20060606133612.B981EF16EC@smtp.263.net>
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> 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 ?
Warner wrote.
> Self Powered just means that the device has told the hub it doesn't
> need any power. These are standard attributes of the device which the
> device reports. FreeBSD just reports these to the user.
--------
mag@intron.ac wrote:
> 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.
Thanks, So my USB to IDE is lieing to FreeBSD. (I had wondered about that).
The chip is labelled:
ALi ("i' is lower case)
M5621 A1
0338 TH05
XHFPAR00000I
Search engines recognise "ALI M5621". Just for interest, I
presume/hope other people with other chips have seen USB to IDE
enclosures that don't lie ? (Caution opening: I blew my first box
(with a different chip) with static by mistake !)
--
Julian Stacey. Consultant Unix Net & Sys. Eng., Munich. http://berklix.com
Mail in Ascii, HTML=spam. Ihr Rauch = mein allergischer Kopfschmerz.
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