Re: random USB disconnect, 2.6.23-rcX

* Alan Stern <[email protected]> wrote:

> > I've noticed a strange USB disconnect of an external HDD. There's
> > several USB devices connected to this machine at all times,
> > mostly hubs, but some directly connected HDD gets hit by this
> > issue.
> > 
> > It's reproducable under normal usage; tho I'm not sure what
> > triggers it. It has happened both while accessing the HDD and
> > during idle times. For what it matters, I replaced the HDD
> > enclosure of a cypress chipset with a genesys logic one...
> > doesn't matter.
> > 
> > 2.6.23-rcX (this one is rc7)
> > 
> > dmesg output:
> > 
> > hub 1-0:1.0: state 7 ports 8 chg 0000 evt 0010 ehci_hcd
> > 0000:00:02.2: GetStatus port 4 status 001002 POWER sig=se0 CSC
> > hub 1-0:1.0: port 4, status 0100, change 0001, 12 Mb/s usb 1-4:
> > USB disconnect, address 3
> 
> That was the disk disconnecting.  Pretty much everything that
> follows is irrelevant: We don't need to know what happened _after_
> the drive disconnected -- we need to know what happened _before_
> (i.e., what caused the disconnect).
>
> A usbmon trace would be helpful.  See the instructions in 
> Documentation/usb/usbmon.txt.

Did that ... nada.

But I tracked this annoying problem down anyway. It turned out it was
solely hardware-related; I used the additional USB-port connectors on
the motherboard (cable->slot) and these little buggers feature a
pretty weak power supply. It's ok if a self-powered hub is connected
to them, but if a device even demands 100 mA it borks (f.e. my old
webcam). Chipset is nvidia (CK8S USB Controller).

-- 
left blank, right bald

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