Hello, I have written a user-space driver for a USB1 spectrometer using libusb. Now there is a new version of the device, which uses USB2. I have adapted my driver for the new protocol that this device uses, but it doesn't work. I have sniffed the Windows driver, and saw one particular difference: the sniffer sees events in this order: - Read request for device. - Write to device. - Write succeeded confirmation. - Read response from device, including data.
Because libusb is synchonous only, what I'm doing is: - Write to device. - Read request to device. - Wait for response (which doesn't usually arrive, although occasionally there is an error response, so there's nothing wrong with the cable etc). I do not really know about the details of the Windows sniffer, but looking at the events, I think the problem might be that the device wants to reply immediately, but didn't see a request, so discards its response. Then when there finally is a request, it doesn't reply anymore. However, I don't know if that is at all possible given the USB protocol. My question is how I can solve this. Would it help to make a kernel driver for it? Could I hack libusb to allow asynchronous reads? Is there any chance that that solves the problem? Any help is welcome. Thanks, Bas Wijnen Ps: Please CC me on replies, I am not subscribed to the list. -- I encourage people to send encrypted e-mail (see http://www.gnupg.org). If you have problems reading my e-mail, use a better reader. Please send the central message of e-mails as plain text in the message body, not as HTML and definitely not as MS Word. Please do not use the MS Word format for attachments either. For more information, see http://pcbcn10.phys.rug.nl/e-mail.html
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