[sane-devel] Problems with libusb and Snapscan 1236U (maybe similar to others): USB dump

m. allan noah anoah@pfeiffer.edu
Mon, 1 Mar 2004 12:44:26 -0500 (EST)

reset is the past tense of reset, since you asked. (dont ask, its 

is there any way for a backend to tell what the current status of the 
toggle is, before closing the connection?


On Mon, 1 Mar 2004, Henning Meier-Geinitz wrote:

> Hi,
> On Mon, Mar 01, 2004 at 11:46:58AM -0500, m. allan noah wrote:
> > if that works, then perhaps there is a libusb/linux kernel error that 
> > prevents the DATA0/1 toggle from frobbing.
> IIRC that's a bug in some USB chipsets. It happens when the connection
> is resetted (?). The USB spec says that in this case the toggle should
> be set to 0. Linux does that but some USB chips (e.g. Mustek 1017)
> doesn't. So everytime the connection is reset with toggle = data1 the
> communication fails. With libusb this happens after every close. With
> the kernel scanner driver only when the module is unloaded. On *BSD
> it also happens with every close().
> So it may not be a bug in the kernel.
> Bye,
>   Henning

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