USB and ACPI bug

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G

Guest

Hi all,

I am wondering whether anyone has encountered a problem whereby the action
of plugging or unplugging a USB device can cause a full computer power reset.
The issue occurs when there are more than 6 usb devices on the bus (on the
computer in general with any arangement of hubs or position on root hubs) and
two of them are based on the Alcor Micro AU6369 chipset. As soon as the
second AU6369 based device is plugged in, the computer resets. No BSOD,
nothing, just a reset. This is very repeatable on a number of different
computers running different versions of Windows XP (we don't have access to
any other OSs to test). If you don't unplug the devices while the computer
powers up again, all the non-AU6369 based devices appear fine, but the AU6369
based units don't even get recognized as being plugged in. I feel very
strongly that this is a bug in the AU6369 chippies but Alcor has not answered
any of my emails so I'm hoping someone here can help out.

Thanx in advance,
S.
 
Update: Alcor has got back to me saying that each of their devices has the
same serial number and during enumeration, windows, if two conflicting serial
numbers are identified, will generate a psudo-random serial number for the
second one. The problem seems to be that the range of this random serial is
very limited and after the generation, is not checked for it's uniqueness.
If windows generates a serial number that is already used, the computer
restarts. First of all, does anyone know whether this is correct and if so,
does anyone know why something this seemingly silly is allowed to happen? I
mean, a restart is a pretty serious concequence for having two of the same
things plugged in to your computer! Any response would be appreciated,
cheers.

S.
 
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