Menu
Ok, I'm probably doing something dumb, but I can't get libusb to let me transfer data to my device for the life of me.
Code:
#include <iostream>
#include <iomanip>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <libusb-1.0/libusb.h>
#define EP_DATA_IN 0x83
#define EP_DATA_OUT 0x02
#define DEVICE_CONFIGURATION 0
int main(int argc, char **argv)
{
int rc;
libusb_context *ctx = NULL;
libusb_device_handle *dev_handle;
int actual = 0;
unsigned char *data = new unsigned char[4];
data[0]='a';data[1]='b';data[2]='c';data[3]='d';
rc = libusb_init(&ctx);
if(rc < 0) {
std::cout << "Init Error " << rc << std::endl;
return 1;
}
libusb_set_debug(ctx, 6);
dev_handle = libusb_open_device_with_vid_pid(ctx, 0x03eb, 0x2423);
if (!dev_handle) {
fprintf(stderr, "Error finding USB device\n");
return 2;
}
if(libusb_kernel_driver_active(dev_handle, DEVICE_CONFIGURATION) == 1) {
std::cout << "Kernel Driver Active" << std::endl;
if(libusb_detach_kernel_driver(dev_handle, DEVICE_CONFIGURATION) == 0)
std::cout << "Kernel Driver Detached!" << std::endl;
}
rc = libusb_claim_interface(dev_handle, DEVICE_CONFIGURATION);
if(rc != 0) {
std::cout << "Cannot Claim Interface" << std::endl;
return 3;
}
std::cout << "Data->" << data << "<-" << std::endl;
std::cout << "Writing Data..." << std::endl;
std::cout << "Trying endpoint " << EP_DATA_OUT << "." << std::endl;
rc = libusb_bulk_transfer(dev_handle, EP_DATA_OUT, data, sizeof(data), &actual, 100);
if(rc == 0 && actual == 4)
{
std::cout << "Writing Successful!" << std::endl;
}
else
{
std::cout << "Write Error! Rc: " << rc << " Actual transfered bytes: " << actual << "." << std::endl;
std::cout << "Error code means: " << libusb_error_name(rc) << std::endl;
}
rc = libusb_release_interface(dev_handle, 0);
if(rc!=0) {
std::cout << "Cannot Release Interface" << std::endl;
return 1;
}
if (dev_handle)
libusb_close(dev_handle);
libusb_exit(ctx);
return 0;
}
Device in question:
pi@testpi:~$ sudo lsusb -d 03eb: -v
Bus 001 Device 004: ID 03eb:2423 Atmel Corp.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x03eb Atmel Corp.
idProduct 0x2423
bcdDevice 1.00
iManufacturer 1 ATMEL ASF
iProduct 2 Vendor Class Example
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 69
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 1
bNumEndpoints 6
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0100 1x 256 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x06 EP 6 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0100 1x 256 bytes
bInterval 1
Device Status: 0x0001
Self Powered
And what I get when I run the code against the device:
pi@testpi:~/BatLogger/Interface/libusb_test$ ./make.sh
libusb: debug [libusb_get_device_list]
libusb: debug [libusb_get_device_descriptor]
libusb: debug [libusb_open] open 1.4
libusb: debug [usbi_add_pollfd] add fd 11 events 4
libusb: debug [libusb_kernel_driver_active] interface 0
libusb: debug [libusb_claim_interface] interface 0
Data->abcd<-
Writing Data...
Trying endpoint 2.
libusb: debug [add_to_flying_list] arm timerfd for timeout in 100ms (first in line)
libusb: debug [submit_bulk_transfer] need 1 urbs for new transfer with length 4
libusb: error [submit_bulk_transfer] submiturb failed error -1 errno=2
libusb: debug [submit_bulk_transfer] first URB failed, easy peasy
libusb: debug [disarm_timerfd]
Write Error! Rc: -1 Actual transfered bytes: 0.
Error code means: LIBUSB_ERROR_IO
libusb: debug [libusb_release_interface] interface 0
libusb: debug [libusb_close]
libusb: debug [usbi_remove_pollfd] remove fd 11
libusb: debug [libusb_exit]
libusb: debug [libusb_exit] destroying default context
As far as I know, I'm doing everything correctly. libusb_claim_interface returns OK, there isn't a pre-existing driver attached to the device since I'm using a custom VID/PID combo, and EP_DATA_OUT is a output endpoint (direction bit is 0, though to whom "out" is with respect to isn't described). Out of irritation, I've also tried every other possible endpoint (0-16, 0-16 | 1 << 7), with the exact same error for all of them.
Is there something silly I'm missing? Do I have to install a kernel module or something to make libusb play nice with me? I'm using libusb-1.0.
The error from the libusb debug message is error -1 errno=2. where errno=2 corresponds to ERNOENT, but the few things I could find about that together with libusb didn't have a decent conclusion about what's actually going on.
Code is built g++ -std=c++11 -Wall -lrt -lusb-1.0 main.cpp -o main.bin, though the fact that I'm using C++ is probably not relevant to the issue, since I'm not using one of the C++ libusb wrappers.
601
Ok, so I figured out the issue.
Basically, apparently, for ~reasons~, the endpoints for my device are attached to configuration 0, alternate setting 1.
I'm not sure how, or if it's even possible to determine this from the output of lsusb, but I had a bit of scripting that I had used for a different device written against PyUSB, so I had a poke around with that, and it told me:
1 pi@testpi:~/BatLogger/Interface/libusb_test$ sudo python3 test.py
INFO:Main.Gui:Device: DEVICE ID 03eb:2423 on Bus 001 Address 004 =================
bLength : 0x12 (18 bytes)
bDescriptorType : 0x1 Device
bcdUSB : 0x200 USB 2.0
bDeviceClass : 0x0 Specified at interface
bDeviceSubClass : 0x0
bDeviceProtocol : 0x0
bMaxPacketSize0 : 0x40 (64 bytes)
idVendor : 0x03eb
idProduct : 0x2423
bcdDevice : 0x100 Device 1.0
iManufacturer : 0x1 ATMEL ASF
iProduct : 0x2 Vendor Class Example
iSerialNumber : 0x0
bNumConfigurations : 0x1
CONFIGURATION 1: 100 mA ==================================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x2 Configuration
wTotalLength : 0x45 (69 bytes)
bNumInterfaces : 0x1
bConfigurationValue : 0x1
iConfiguration : 0x0
bmAttributes : 0xc0 Self Powered
bMaxPower : 0x32 (100 mA)
INTERFACE 0: Vendor Specific ===========================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x0
bAlternateSetting : 0x0
bNumEndpoints : 0x0
bInterfaceClass : 0xff Vendor Specific
bInterfaceSubClass : 0xff
bInterfaceProtocol : 0xff
iInterface : 0x0
INTERFACE 0, 1: Vendor Specific ========================
bLength : 0x9 (9 bytes)
bDescriptorType : 0x4 Interface
bInterfaceNumber : 0x0
bAlternateSetting : 0x1
bNumEndpoints : 0x6
bInterfaceClass : 0xff Vendor Specific
bInterfaceSubClass : 0xff
bInterfaceProtocol : 0xff
iInterface : 0x0
ENDPOINT 0x81: Interrupt IN ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x81 IN
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x1
ENDPOINT 0x2: Interrupt OUT ==========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x2 OUT
bmAttributes : 0x3 Interrupt
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x1
ENDPOINT 0x83: Bulk IN ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x83 IN
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x0
ENDPOINT 0x4: Bulk OUT ===============================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x4 OUT
bmAttributes : 0x2 Bulk
wMaxPacketSize : 0x40 (64 bytes)
bInterval : 0x0
ENDPOINT 0x85: Isochronous IN ========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x85 IN
bmAttributes : 0x1 Isochronous
wMaxPacketSize : 0x100 (256 bytes)
bInterval : 0x1
ENDPOINT 0x6: Isochronous OUT ========================
bLength : 0x7 (7 bytes)
bDescriptorType : 0x5 Endpoint
bEndpointAddress : 0x6 OUT
bmAttributes : 0x1 Isochronous
wMaxPacketSize : 0x100 (256 bytes)
bInterval : 0x1
The critical thing being that there are no endpoints under INTERFACE 0:, but there are endpoints under INTERFACE 0, 1:. This was enough to go on to figure out that there were more then one version of INTERFACE 0, and with that, it was pretty easy to figure out I needed to call libusb_set_interface_alt_setting() to select the right alternate configuration thingie.
Basically, I wound up adding
rc = libusb_set_interface_alt_setting(dev_handle, DEVICE_CONFIGURATION, 1);
if(rc != 0) {
std::cout << "Cannot configure alternate setting" << std::endl;
return 3;
}
after the libusb_claim_interface() call in my C(++) code, and I can now write to the device.
182
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With