On Monday 11 October 2004 05:09 pm, Mark Jarvis wrote:
>
> Nope. One device is a standard flash memory "thumb" or "lipstick"
> drive. It plugs into a standard USB port. The other device is [a SD
> memory card more-or-less permanently inserted in a SD card reader].
> (Note brackets.) The SD card reader plugs into a standard USB port.
>
> It's equivalent to swapping two std. flash drives in one USB port and
> works the same at home (both a SCSI drive & a USB drive present) and at
> school (just USB). First drive seen always works. Second(swapped in)
> drive always fails. Haven't played around with it as much at school, but
> get basically the same results when using my flash drive & a borrowed
> drive.
>
> I shouldn't have mentioned the SD card. Don't bother going there. If the
> SD card/reader combo is seen first it works fine. The issue is swapping
> two (or more) USB flash memory drives in & out of a single connection
> point.
OK! Now I understand. Now we can proceed as I would proceed.
First, we need to see what the USB is doing as you connect and disconned the
USB device. The best way to do that, in my experience, is to use usbview.
It is a utility that displays a "tree" view of the USB connections and
devices. You can watch as you plug something in and as it goes away when you
remove it. You might have it already but I have always had to install it
separately. Try
http://www.kroah.com/linux-usb/. I have always had good
luck with the binary RPM file or you can install and build from the source.
Now, boot your computer without any devices plugged into the USB. Start
usbview and position it so you can see it. Now plug one of the devices into
the end of your cable. It should get loaded into the USB tree view and be
identified, etc.
Now, disconnect it from the USB. It should disapper from the USB tree. If
not, that is the problem. The hotswap is not removing the device.
Now, connect the other USB device. It should come up in the tree view with
it's own unique information. If it does not, the hotswap is not adding the
device.
Now (I'm saying "Now' too much), we will have to figure out what to do next
based on what you learn here.
As an aside, I have found USB to be unstable on some computers. I have a
Compaq computer here that will not reconnect a USB device on any port that
already had a device connected. Everything is setup "right" but if I sync my
palm on one port and then try to plug something else in that same port, the
something else will not be seen. On that particular computer, the only way
to reset that bogus USB situation is to reboot (yuck!). I did not dig
further to solve it since, at the time, I just left the printer plugged into
it's port and only used the other for my palm.
I guess what I am saying is that to really solve the problem, we may have to
venture deep into the driver tree before we are done. Just a small warning.
Alan
>
> BTW, having trouble getting one student's Memorex flash drive to work at
> all. (Other students' flash drives are OK.)
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