Hi all,
Some members of the IVI Foundation www.ivifoundation.org have founded a
working group “VISA for Linux” that defines common rules, header files,
and shared libraries for Linux to implement the specification of "VPP-4.3:
The VISA Library" (see
http://ivifoundation.org/specifications/default.aspx).
Moreover the interoperability of the USBTMC protocol is one of our
requirements. We know that you have already improved the Linux USBTMC
driver (linux/drivers/usb/class/usbtmc.c) that can communicate with T&M
instruments. However we are not sure whether this driver already includes
all features that we need for our instruments and for the VISA API.
Therefore we ask you to give us some recommendations or replies to our
questions:
1. "Libusb" versus usbtmc driver: Using "libusb" seems to be a good
alternative for all Linux platforms and is the right fallback solution
until future versions of the USBTMC includes all required features. Do you
think we should extend the USBTMC driver with our required features (e.g.
vendor specific IO, SRQ handling, asynchronous IO, raw USB IO, timeout)?
Or do you think we shall keep the USBTMC driver in the current state? How
long would it take to get changes into the Linux kernel?
2. As we have looked at the Linux driver, we’ve noticed that performance
of the usbtmc_read() function doesn’t keep up with our fastest
instruments. Do you have any suggestions on how to improve the read
performance?
3. Do you have any plans to modify/evolve the USBTMC driver moving
forward?
4. Do you know of any other differences between the Linux USBTMC driver
and the Windows USBTMC driver?
We are looking forward to your comments. Please let us know if some of you
would like to participate to the next WebEx conference call.
-Guido
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