On 05/22/2013 12:27 PM, Alan Stern wrote:
On Wed, 22 May 2013, Joe Julian wrote:
On 05/21/2013 03:20 PM, Joe Julian wrote:
I have about 100 of these creditcard/check scanners that are dropping
events. I was able to find some overflows that I assume are probably
related to the problem, "usb 4-1: ctrl urb status -75 received".
Short of asking the vendor to fix their product or compiling a custom
kernel, are there any other options? Can the MaxPacketSize or the
buffer size be overridden somehow (/sys/bus/usb/devices... maybe)?
I have started a dialog with UIC (Uniform Industrial Corp) about a fix,
but I'm not very hopeful. Is there anything I can do to work around the
overflow?
Without knowing more (like where the overflows occur and what data was
expected), it is impossible to answer this question. A usbmon trace
would help.
Simply changing the bMaxPacketSize0 value is extremely unlikely to
work.
Thanks. I have a usbmon capture of a failed event, but since this is a
credit card scan I need to at least interpret and obfuscate the card
data. For a keystroke there seems to be two events each, the key press
(00003800) and the key release (00000000), each being the 8 bytes I
would expect. Some, however, start with 02 (02003800). Is that for a
shift key? I see a sequence like 02000000 02000d00 00000d00 00000000
which I suspect must be a "%" key (shift down, 5 down, shift up, 5 up).
Is that correct?
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