问题
I was trying to enumerate usb cdc device using pic24fj128gb206. Device seems to be enumerated properly.
But when I connect my device to Linux PC, I am getting the below warning message from kernel.
cdc_acm 1-8.1.6.7:1.0: failed to set dtr/rts
And this message will repeat when I try to connect using screen.
screen /dev/ttyACM9 115200
And I am not able to communicate with my device from PC [ Ubuntu, 14.04 ]
When analysing the data using wireshark, it looks like USB communication is fine until, host issues URB_CONTROL_out and the device responds with
URB status as Broken Pipe (-EPIPE ) (-32)
Can any one help me with how to debug this issue or any methods to debug further ?
来源：https://stackoverflow.com/questions/39281814/cdc-acm-failed-to-set-dtr-rts-can-not-communicate-with-usb-cdc-device