gregkh / usbutils

USB utilities for Linux, including lsusb
http://www.linux-usb.org
354 stars 199 forks source link

Retrieving interface descriptors #155

Closed symdeb closed 2 years ago

symdeb commented 2 years ago

Just a question. Does the library support control transfer to retrieve interface descriptors ? I have a case for a project where a call not seem to reach the SETUP stage code for an embedded controller firmware:

The device is just plugged in, no drivers are using it. After plugging in Linux did set the address (0x05) and configure (0x09) and retrieved the string descriptors successfully. After that no transactions are done. Then using libusb the following call is issues: int ret = libusb_control_transfer(handle,0x81,0x06,0x2601,1,data,5,0); Libusb returns an error -1: Input/Output Error but using this (device) does reach the firmware: int ret = libusb_control_transfer(handle,0x80,0x06,0x2601,1,data,5,0); I am trying to figure out how to further nail down if this is related to libusb or the firmware. The firmware code is quite complex and have not yet found out where this gets stuck

posted this ib thelibusb repo. This can be closed.