On 2/2/20 6:18 AM, Rich Shepard wrote:
My desktop host has an Asus Prime X470-Pro motherboard and USB3.x ports on
the rear panel plus two on the front panel.
I have a 7-port USB3.x hub connected to one of the rear ports. The external
backup drive, Palm TX sync/charger, and the Nokia phone charger are
connected to that hub. But, when I connect the Canon Canoscan LiDE 400 to
the hub neither 'scanimage -L' nor 'sane-find-scanner' sees it.
snip
I don't now know which flavor of USB3.x powers the hub and front port and
wonder why this would make a difference in sane (and I presume xsane)
finding the scanner.
I suspect you are over the power budget for your bus-powered hub.
Before trying sane, I suggest using lsusb to check for the scanner.
This command will tell you how much power every USB device is
requesting. Look for your hub and the connected devices and add up the
current. The limit for USB 3.0 is 900 mA total current.
lsusb -v |grep 'idVendor\|idProduct\|MaxPower'
Try it with the scanner connected in both places just in case the
scanner doesn't even appear when connected to the hub.
I think this answer is generally correct.
<https://superuser.com/questions/1460313/what-is-the-maximum-power-supplied-by-a-usb-3-0-port>
If you have a USB charging port on the rear panel (probably a yellow
connector), try connecting to that. It *may* allow you to go up to 1500
mA, but I'm not sure. It's possible that this higher current is only
available to things that are being charged, like cell phones. I don't
know whether a hub could take advantage of the extra current or not.
Given what you have connected, I think the solution is probably going to
be connecting power to the hub.
galen
--
Galen Seitz
[email protected]
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