[sane-devel] Some weirdness with a Canon LiDE 220

[m. allan noah]

On Wed, Dec 16, 2015 at 3:45 PM, Scott Alfter <scott at alfter.us> wrote:
> On 12/16/2015 2:42 AM, Johannes Meixner wrote:
>> On Dec 15 13:29 Scott Alfter wrote (excerpt):
>>> The new motherboard supports USB 3.0 as well as 2.0
>>
>> Really pure traditional USB 2 hardware?
>>
>> In general when your scanner is connected via USB:
>>
>> There are currently issues with USB ports where the kernel
>> module "xhci" is used as kernel driver.
>>
>> When "lsusb -t" shows "Driver=xhci_hcd" for the USB bus and
>> port where the USB scanner is connected (see "lsusb" where
>> the scanner is connected), then there could be issues
>> depending on the computer hardware and firmware.
>
> I brought my scanner in to work to test it with an older machine that
> only provides USB 2.0. As I suspected (though not on account of possible
> USB issues), it ran like a champ here, even though it was running in a
> VM, not on the metal. (As an aside, VirtualBox's support for passing USB
> devices through to guests really appears to have improved with v5.0.)
>
> Since it's at work, I can't test it at home, but lsusb -t shows the
> following for the home system:
>
> /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
> /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/14p, 480M
> |__ Port 3: Dev 2, If 0, Class=Wireless, Driver=, 12M
> |__ Port 3: Dev 2, If 1, Class=Wireless, Driver=, 12M
> |__ Port 4: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 12M
> |__ Port 5: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
> |__ Port 9: Dev 5, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
> |__ Port 13: Dev 6, If 0, Class=Video, Driver=, 480M
> |__ Port 13: Dev 6, If 1, Class=Video, Driver=, 480M
> |__ Port 13: Dev 6, If 2, Class=Audio, Driver=snd-usb-audio, 480M
> |__ Port 13: Dev 6, If 3, Class=Audio, Driver=snd-usb-audio, 480M
> /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
> |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
> /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
> |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
>
> At this time, it has a keyboard, mouse, webcam, Bluetooth dongle, and
> ANT+ dongle plugged in. I filled the "USB 2.0" (black) ports up before I
> started plugging things into USB 3.0 (blue) ports, yet it looks like
> everything's going through the xhci_hcd driver.
>
> Looks like a separate USB 2.0 interface is in order...a minor annoyance,
> but at least it's a cheap fix.
>

if you are able to build sane-backends from source, we could try
disabling a workaround I added for Linux USB3 problems. That might
help.

allan
-- 
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"