Re: [Libusb-devel] Errors writing to bulk-out endpoint

[Peter S. <pe...@st...>]

Hi Mark,

Mark E Mason wrote:
> I'm new to libusb, but not to USB programming in general. I have a
> device with 2 interfaces. The second interface has two bulk
> endpoints (one in and one out). I've coded up a test program that
> (after finding my device and claiming the interface) attempts to
> write 32 bytes of data to the OUT endpoint. I'm getting back an
> EPROTO (-71) error from the kernel when this happens. Any ideas?

EPROTO from the kernel means that there was a low-level bus protocol
error. libusb-wise you're doing it right.

What happens in your device during this transfer? Can you tell if it
ACKs the packet?

Have you been able to perform the same transfer without libusb? If
yes, which system and how did that code look?


//Peter