libusb error when doing libusb_control_transfer
I'm trying to control a USB webcam device by following what is mentioned on this thread: https://sourceforge.net/p/linux-uvc/mailman/message/35920367/. That thread says:
You can also send direct USB commands in C, allowing you to work around the firmware misbehaviour by ignoring the UVC spec. Something like:
memcpy(buf, "\x80\x01\xF1", 3);
ret = usb_control_msg(devh, USB_TYPE_CLASS + USB_RECIP_INTERFACE, 0x01, 0x0300, 0x0400, buf, 3, 1000);
My code looks like:
#include <stdio.h>
#include <string.h>
#include "libusb.h"
int main(int argc, char **argv) {
libusb_context *context = NULL;
libusb_init(&context);
libusb_device_handle *devh;
devh = libusb_open_device_with_vid_pid(context, 0xa168, 0x0710);
fprintf(stderr, "devh:%lu\n", (long unsigned)devh);
libusb_detach_kernel_driver(devh, 0);
libusb_claim_interface(devh, 0);
char buf[3];
memcpy(buf, "\x80\x01\xf1", 3);
uint8_t bmReqType = 32 + 1;// the request type (direction of transfer)
uint8_t bReq = 1;// the request field for this packet
uint16_t wVal = 0x300;// the value field for this packet
uint16_t wIndex = 0x400;// the index field for this packet
int r = libusb_control_transfer(devh, bmReqType, bReq, wVal, wIndex, buf, 3, 1000);
fprintf(stderr, "libusb_control_transfer returns %d\n", r);
libusb_close(devh);
libusb_exit(NULL);
}
I'm getting either LIBUSB_ERROR_IO (-1) or LIBUSB_ERROR_PIPE (-9).
The USB device is reported as:
Bus 001 Device 033: ID a168:0710 AnMo Electronics Corporation
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0xa168 AnMo Electronics Corporation
idProduct 0x0710
bcdDevice 24.14
iManufacturer 2 AnMo Electronics Corporation
iProduct 1 Dino-Lite Premier
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0239
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 14 Video
bFunctionSubClass 3 Video Interface Collection
bFunctionProtocol 0
iFunction 5 Dino-Lite Premier
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 1 Video Control
bInterfaceProtocol 0
iInterface 5 Dino-Lite Premier
VideoControl Interface Descriptor:
bLength 13
bDescriptorType 36
bDescriptorSubtype 1 (HEADER)
bcdUVC 1.00
wTotalLength 0x0067
dwClockFrequency 15.000000MHz
bInCollection 1
baInterfaceNr( 0) 1
VideoControl Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 2
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0
bSourceID 5
iTerminal 0
VideoControl Interface Descriptor:
bLength 26
bDescriptorType 36
bDescriptorSubtype 6 (EXTENSION_UNIT)
bUnitID 4
guidExtensionCode {28f03370-6311-4a2e-ba2c-6890eb334016}
bNumControl 8
bNrPins 1
baSourceID( 0) 3
bControlSize 1
bmControls( 0) 0x0f
iExtension 0
VideoControl Interface Descriptor:
bLength 26
bDescriptorType 36
bDescriptorSubtype 6 (EXTENSION_UNIT)
bUnitID 5
guidExtensionCode {2812ae3f-bcd7-4e11-a357-6f1edef7d61d}
bNumControl 8
bNrPins 1
baSourceID( 0) 4
bControlSize 1
bmControls( 0) 0xff
iExtension 0
VideoControl Interface Descriptor:
bLength 18
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 1
wTerminalType 0x0201 Camera Sensor
bAssocTerminal 0
iTerminal 0
wObjectiveFocalLengthMin 0
wObjectiveFocalLengthMax 0
wOcularFocalLength 0
bControlSize 3
bmControls 0x00000000
VideoControl Interface Descriptor:
bLength 11
bDescriptorType 36
bDescriptorSubtype 5 (PROCESSING_UNIT)
Warning: Descriptor too short
bUnitID 3
bSourceID 1
wMaxMultiplier 0
bControlSize 2
bmControls 0x0000072f
Brightness
Contrast
Hue
Saturation
Gamma
Backlight Compensation
Gain
Power Line Frequency
iProcessing 0
bmVideoStandards 0x00
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0010 1x 16 bytes
bInterval 6
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
VideoStreaming Interface Descriptor:
bLength 14
bDescriptorType 36
bDescriptorSubtype 1 (INPUT_HEADER)
bNumFormats 1
wTotalLength 0x0143
bEndPointAddress 129
bmInfo 0
bTerminalLink 2
bStillCaptureMethod 2
bTriggerSupport 0
bTriggerUsage 0
bControlSize 1
bmaControls( 0) 0
VideoStreaming Interface Descriptor:
bLength 27
bDescriptorType 36
bDescriptorSubtype 4 (FORMAT_UNCOMPRESSED)
bFormatIndex 1
bNumFrameDescriptors 5
guidFormat {32595559-0000-0010-8000-00aa00389b71}
bBitsPerPixel 16
bDefaultFrameIndex 1
bAspectRatioX 0
bAspectRatioY 0
bmInterlaceFlags 0x00
Interlaced stream or variable: No
Fields per frame: 2 fields
Field 1 first: No
Field pattern: Field 1 only
bCopyProtect 0
VideoStreaming Interface Descriptor:
bLength 50
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 1
bmCapabilities 0x00
Still image unsupported
wWidth 640
wHeight 480
dwMinBitRate 3072000
dwMaxBitRate 18432000
dwMaxVideoFrameBufferSize 614400
dwDefaultFrameInterval 333333
bFrameIntervalType 6
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666666
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 2000000
VideoStreaming Interface Descriptor:
bLength 50
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 2
bmCapabilities 0x00
Still image unsupported
wWidth 352
wHeight 288
dwMinBitRate 1013760
dwMaxBitRate 6082560
dwMaxVideoFrameBufferSize 202752
dwDefaultFrameInterval 333333
bFrameIntervalType 6
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666666
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 2000000
VideoStreaming Interface Descriptor:
bLength 50
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 3
bmCapabilities 0x00
Still image unsupported
wWidth 320
wHeight 240
dwMinBitRate 768000
dwMaxBitRate 4608000
dwMaxVideoFrameBufferSize 153600
dwDefaultFrameInterval 333333
bFrameIntervalType 6
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666666
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 2000000
VideoStreaming Interface Descriptor:
bLength 50
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 4
bmCapabilities 0x00
Still image unsupported
wWidth 176
wHeight 144
dwMinBitRate 253440
dwMaxBitRate 1520640
dwMaxVideoFrameBufferSize 50688
dwDefaultFrameInterval 333333
bFrameIntervalType 6
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666666
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 2000000
VideoStreaming Interface Descriptor:
bLength 50
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 5
bmCapabilities 0x00
Still image unsupported
wWidth 160
wHeight 120
dwMinBitRate 192000
dwMaxBitRate 1152000
dwMaxVideoFrameBufferSize 38400
dwDefaultFrameInterval 333333
bFrameIntervalType 6
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666666
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 2000000
VideoStreaming Interface Descriptor:
bLength 26
bDescriptorType 36
bDescriptorSubtype 3 (STILL_IMAGE_FRAME)
bEndpointAddress 0
bNumImageSizePatterns 5
wWidth( 0) 640
wHeight( 0) 480
wWidth( 1) 352
wHeight( 1) 288
wWidth( 2) 320
wHeight( 2) 240
wWidth( 3) 176
wHeight( 3) 144
wWidth( 4) 160
wHeight( 4) 120
bNumCompressionPatterns 0
VideoStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 13 (COLORFORMAT)
bColorPrimaries 1 (BT.709,sRGB)
bTransferCharacteristics 1 (BT.709)
bMatrixCoefficients 4 (SMPTE 170M (BT.601))
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0080 1x 128 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 2
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0100 1x 256 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 3
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0320 1x 800 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 4
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0b20 2x 800 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 5
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x1320 3x 800 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 6
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x1400 3x 1024 bytes
bInterval 1
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0002
(Bus Powered)
Remote Wakeup Enabled
Any idea what I'm doing wrong?
asked on Stack Overflow Sep 11, 2020 by 
gregoiregentil
gregoiregentil1 Answer
Sadly I don't own this device anymore so I cannot test your code.
It looks fine though, the length stuff is correct. My only suggestions from there would be:
running your code as root in case this is a simple permission issue
checking dmesg in case the kernel output some useful messages
debugging further by:
- using a USB traffic analyzer (Wireshark works fairly well) though it's likely you won't see anything because the error happens in the kernel driver at TX
- turning on some kernel debugging features and try to hook into the drivers to understand where the error comes from: https://www.kernel.org/doc/html/v4.18/dev-tools/kgdb.html, https://www.kernel.org/doc/html/v4.18/trace/events.html
Good luck with troubleshooting.
answered on Stack Overflow Sep 12, 2020 by 
zopieux
zopieuxUser contributions licensed under CC BY-SA 3.0