Re: Why USB device is repeatedly disconnecting & reconnecting?
- From: "M.I.5¾" <no.one@xxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 13 Nov 2008 11:35:10 -0000
"VanguardLH" <V@xxxxxxxxx> wrote in message
news:gfgh5o$oo0$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
sgopus wrote:
"VanguardLH" wrote:
I have a USB device that repeatedly disconnecting and connecting (i.e.,
stopping and restarting). This happens at random times throughout the
day and every day. I will hear the beep-boop disconnect sound notifying
me that the PnP device was stopped (disconnected). A couple seconds
later is the boop-beep connect sound telling me the PnP device was
started (connected). Due to the reconnect, auto-play kicks off the
autorun.exe on the emulated CD device. If I'm not at the computer to
heep the PnP sound events, or if I have the speakers muted, I won't know
about the start-stop bouncing of the USB device.
So I need advice on how to monitor or track down what might be causing a
USB device to get stopped and then restarted. There is nothing in the
Event Viewer to indicate a problem at the time the USB device gets
bounced. The PnP monitor ("Safely Remove Hardware") icon is in the
system tray when the USB device is started. I can use the tray icon to
see the monitored USB devices (or run "rundll32.exe
shell32.dll,Control_RunDLL hotplug.dll" if the tray icon is missing).
But I need something to tell me why the USB device got disconnected in
the first place (and then it gets detected again and reconnected). I'm
trying to determine how to monitor what could be disconnecting the USB
device.
are you connecting to a USB hug, with it's own power supply?
power flucuations could be causing this if you don't have adquate power
to
the USB device.
Nope, plugging into a USB port on the system case (so it comes directly
from the USB controller on the motherboard).
USB ports come in pairs because the USB controller can manage 2
channels; however, the other USB port is not used so the 500mA available
for total load from the controller is available to the single USB device
(which is has the problem). So it is not a problem of 2 USB devices
sucking more power from the paired USB port set than the controller can
deliver.
Despite that fact that the ports are paired on the OHCI root hubs, the full
500mA will be available from both ports on the root hub. Similarly, 500mA
will be available from all 6 ports on the single EHCI root hub.
There are 6 USB ports on this host (i.e., 3 sets of paired ports) and
moving the device to each of the 3 USB sets of ports does not eliminate
the problem. In each port where this problematic USB device keeps
getting erratically disconnected and reconnected, other USB devices
don't experience this behavior. My USB printer doesn't disappear and
reappear, nor does my USB thumb drive.
It may have helped us to help you had you divulged what this mystery device
is. Without knowing what it is, any response you get here will be, at best,
a wild guess.
.
- References:
- Why USB device is repeatedly disconnecting & reconnecting?
- From: VanguardLH
- RE: Why USB device is repeatedly disconnecting & reconnecting?
- From: sgopus
- Re: Why USB device is repeatedly disconnecting & reconnecting?
- From: VanguardLH
- Why USB device is repeatedly disconnecting & reconnecting?
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