I took a look at the capacitors on all of my PCI USB 2.0
host adapters, and thought it would be helpful to post that
information along with the experimental results.
Card Vendor Chip Capacitor # of other P4/Titan me600
vendor at each port capictors result result
P4/Titan Intel ? ? [note 1] n/a
motherboard ich4/5
me600 Cyrix ? ? n/a usb-2.0
motherboard
? ALi 10uF 4 usb-1.1 usb-1.1
m5273a1
? VIA 100uF 5 usb-2.0 usb-2.0
vt6202
Syba NEC 100uF 7 usb-2.0 untested
?
[1] The built-in ports on the Titan P4 ga-8i875 motherboard connect
to USB-2.0 devices as USB-2.0, but my Avision av220 scanner consistently
get a timeout after the avision driver successfully completes about
three encapsulated USB SCSI requests. My usb-2.0 CompactFlash
adapter seems to work fine as a USB-2.0 device thought.
In the "result" columns on the right, "usb-1.1" means that usb-2.0
devices connect as 12mbps usb-1.1 devices, even though the controller
is supposed to be a usb-2.0 controller.
Note that the VIA controller consistently reports an overcurrent
condition when trying (and failing) to initialize any USB-2.0 device
when the controller card is plugged into the P4/Titan motherboard.
This and the fact the card that works with my P4/Titan motherboard
is the card with the most capacitors (the Syba NEC card) makes
me suspicious that this might be an analog hardware issue.
If this is an analog hardware issue relating to power
in the first fraction of a second when the cable is
being plugged in and the controller is listening for a
USB 2.0 "chirp" signal, then I wonder if it might be
possible to try doing a host-initiated port reset a
second time after a delay if the first one fails.
__ ______________
Adam J. Richter \ /
[EMAIL PROTECTED] | g g d r a s i l
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