[libhid-discuss] Input and Output ports

[ankita prasad]

Hi all,

Thanks for all your help till now. The firmware on the HID device does not
have the correct report descriptor. But the guys who made teh firmware sent
me what the report descriptor should contain. So I hard coded it in the
parser functions and now I can read and write to my HID device. The input
and the output ports are the same being 0x81.

I just want to confirm that I am correct in my above assumption abt the
input and output ports( i don't get any errors when I run hid_interrupt
write and hid_interrupt_read)

This is the output of my lsusb -vvv

Bus 001 Device 037: ID 0694:0003 abc Group
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         8
  idVendor           0x0694 abc Group
  idProduct          0x0003
  bcdDevice            0.11
  iManufacturer           0
  iProduct                2 abc USB Hub V0.11
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xa0
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              0
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      37
          Report Descriptor: (length is 37)
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x3b ] 59
                            Byte Count
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0xff 0x00 ] 255
            Item(Local ): Usage Minimum, data= [ 0x10 ] 16
                            (null)
            Item(Local ): Usage Maximum, data= [ 0x17 ] 23
                            (null)
            Item(Global): Report Count, data= [ 0x08 ] 8
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Main  ): Input, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile
Bitfield
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0xff 0x00 ] 255
            Item(Local ): Usage Minimum, data= [ 0x18 ] 24
                            (null)
            Item(Local ): Usage Maximum, data= [ 0x1f ] 31
                            (null)
            Item(Global): Report Count, data= [ 0x08 ] 8
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Main  ): Output, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile
Bitfield
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval              10

Could you guys look at this and tell me whether I am correct in my
assumption? Any confirmation would help me proceed further.

Thanks a ton!
Ankita