Red Hat Bugzilla – Bug 229654
USB 2.0 transfer size limit problem: Vuescan does not recognize scanner
Last modified: 2008-04-04 07:35:06 EDT
Description of problem:
Vuescan 8.3.87 does not recognize a Minolta Scan Dual III scanner on a desktop
machine with a fresh install of FC5 updated via yum. An exchange of emails with
the developer of Vuescan concludes: "This would indicate a kernel problem . . .,
probably in the USB subsystem limiting transfers to 32 KBytes." "The problem is
that when VueScan tries to load the firmware into the scanner, it tries to
transfer 44904 bytes in a single transfer. This is failing." Connecting the
scanner to the motherboard's USB 1.0 port results in proper function of the Dual
III, so the problem seems to be confined to USB 2.0. So far I have not been
able to identify where this transfer limit is established - via an option passed
to a kernel module or within a module itself.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. delete ~/.vuescan
2. shut down and remove power from scanner and computer; plug scanner into USB
3. boot computer
4. turn on scanner
5. run vuescan: observe that vuescan properly identifies the scanner as a Dual
III, but that the scanner responds to no vuescan commands such as "Calibrate" or
Scanner responds to no vuescan commands such as "Calibrate" or "Scan"
Scanner calibaration or scan activity in response to these commands.
32KB sounds like a limit on the single URB size as enforced by usbfs.
But if so, it would affect both speeds. Something does not compute
about this report.
What's the e-mail of the Vuescan guy?
Downloaded the latest version of Vuescan (8.4.12). Same problem: Vuescan works
through the USB 1.0 port, but fails through the USB 2.0 port. Now running
Tried a different computer: Vuescan works with the Minolta Scan Dual III
scanner when connected to a Zonet ZUN2200 USB 2.0 Cardbus PC Card on a Thinkpad
600E also running Vuescan 8.4.12 and kernel 2.6.19-1.2288.fc5. Perhaps this bug
is card-specific? The non-working card is a "CTG USB 2.0 Hi-Speed 5-Port PCI
Card", Tiger Direct Item No. C184-29554, purchased in November, 2006. This card
works well with a variety of devices including an Epson Perfection 1260 flat-bed
scanner being driven by Vuescan 8.4.12 - the Minolta Scan Dual III is the only
device tried so far that has not worked with it.
This problem persists under kernel 2.6.20-1.2307.fc5
This problem is "fixed" by: rmmod ehci_hcd
The problem seems to be card-specific. The card in question is a "Cables To Go
USB 2.0 Hi-Speed 5-Port PCI Card", item number C184-29554 at Tiger Direct.
Replacing this card with an "IOFuture PU520 High-Speed USB 2.0 PCI Host
Controller", item number 15-104-216 at NewEgg, caused this and some other
strange USB-related problems to go away.
Fedora apologizes that these issues have not been resolved yet. We're
sorry it's taken so long for your bug to be properly triaged and acted
on. We appreciate the time you took to report this issue and want to
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