我尝试了解如何查找 USB 设备报告长度。
其中lsusb -vvv，没有有关报告描述内容或大小的信息：
Bus 002 Device 003: ID 045e:0752 Microsoft Corp. Wired Keyboard 400
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x045e Microsoft Corp.
idProduct 0x0752 Wired Keyboard 400
bcdDevice 3.00
iManufacturer 1 Microsoft
iProduct 2 Wired Keyboard 400
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 1 Boot Interface Subclass
bInterfaceProtocol 1 Keyboard
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.11
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 65
Report Descriptors:
** UNAVAILABLE **
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
Device Status: 0x0000
(Bus Powered)
然后我尝试从 sys 条目中执行 cat rdesc： sudo cat /sys/kernel/debug/hid/0003:045E:0752.0002/rdesc 并得到以下结果：
05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 75 01 95 08 81 02 95 01 75 08 81 01 95 05 75 01 05 08 19 01 29 05 91 02 95 01 75 03 91 01 95 06 75 08 15 00 26 ff 00 05 07 19 00 2a ff 00 81 00 c0
INPUT[INPUT]
Field(0)
Application(GenericDesktop.Keyboard)
Usage(8)
Keyboard.00e0
Keyboard.00e1
Keyboard.00e2
Keyboard.00e3
Keyboard.00e4
Keyboard.00e5
Keyboard.00e6
Keyboard.00e7
Logical Minimum(0)
Logical Maximum(1)
Report Size(1)
Report Count(8)
Report Offset(0)
Flags( Variable Absolute )
Field(1)
Application(GenericDesktop.Keyboard)
Usage(256)
Keyboard.0000
Keyboard.0001
Keyboard.0002
Keyboard.0003
Keyboard.0004
Keyboard.0005
Keyboard.0006
Keyboard.0007
Keyboard.0008
Keyboard.0009
Keyboard.000a
Keyboard.000b
Keyboard.000c
Keyboard.000d
Keyboard.000e
Keyboard.000f
Keyboard.0010
Keyboard.0011
Keyboard.0012
Keyboard.0013
Keyboard.0014
Keyboard.0015
Keyboard.0016
Keyboard.0017
Keyboard.0018
Keyboard.0019
Keyboard.001a
Keyboard.001b
Keyboard.001c
Keyboard.001d
Keyboard.001e
Keyboard.001f
Keyboard.0020
Keyboard.0021
Keyboard.0022
Keyboard.0023
Keyboard.0024
Keyboard.0025
Keyboard.0026
Keyboard.0027
Keyboard.0028
Keyboard.0029
Keyboard.002a
Keyboard.002b
Keyboard.002c
Keyboard.002d
Keyboard.002e
Keyboard.002f
Keyboard.0030
Keyboard.0031
Keyboard.0032
Keyboard.0033
Keyboard.0034
Keyboard.0035
Keyboard.0036
Keyboard.0037
Keyboard.0038
Keyboard.0039
Keyboard.003a
Keyboard.003b
Keyboard.003c
Keyboard.003d
Keyboard.003e
Keyboard.003f
Keyboard.0040
Keyboard.0041
Keyboard.0042
Keyboard.0043
Keyboard.0044
Keyboard.0045
Keyboard.0046
Keyboard.0047
Keyboard.0048
Keyboard.0049
Keyboard.004a
Keyboard.004b
Keyboard.004c
Keyboard.004d
Keyboard.004e
Keyboard.004f
Keyboard.0050
Keyboard.0051
Keyboard.0052
Keyboard.0053
Keyboard.0054
Keyboard.0055
Keyboard.0056
Keyboard.0057
Keyboard.0058
Keyboard.0059
Keyboard.005a
Keyboard.005b
Keyboard.005c
Keyboard.005d
Keyboard.005e
Keyboard.005f
Keyboard.0060
Keyboard.0061
Keyboard.0062
Keyboard.0063
Keyboard.0064
Keyboard.0065
Keyboard.0066
Keyboard.0067
Keyboard.0068
Keyboard.0069
Keyboard.006a
Keyboard.006b
Keyboard.006c
Keyboard.006d
Keyboard.006e
Keyboard.006f
Keyboard.0070
Keyboard.0071
Keyboard.0072
Keyboard.0073
Keyboard.0074
Keyboard.0075
Keyboard.0076
Keyboard.0077
Keyboard.0078
Keyboard.0079
Keyboard.007a
Keyboard.007b
Keyboard.007c
Keyboard.007d
Keyboard.007e
Keyboard.007f
Keyboard.0080
Keyboard.0081
Keyboard.0082
Keyboard.0083
Keyboard.0084
Keyboard.0085
Keyboard.0086
Keyboard.0087
Keyboard.0088
Keyboard.0089
Keyboard.008a
Keyboard.008b
Keyboard.008c
Keyboard.008d
Keyboard.008e
Keyboard.008f
Keyboard.0090
Keyboard.0091
Keyboard.0092
Keyboard.0093
Keyboard.0094
Keyboard.0095
Keyboard.0096
Keyboard.0097
Keyboard.0098
Keyboard.0099
Keyboard.009a
Keyboard.009b
Keyboard.009c
Keyboard.009d
Keyboard.009e
Keyboard.009f
Keyboard.00a0
Keyboard.00a1
Keyboard.00a2
Keyboard.00a3
Keyboard.00a4
Keyboard.00a5
Keyboard.00a6
Keyboard.00a7
Keyboard.00a8
Keyboard.00a9
Keyboard.00aa
Keyboard.00ab
Keyboard.00ac
Keyboard.00ad
Keyboard.00ae
Keyboard.00af
Keyboard.00b0
Keyboard.00b1
Keyboard.00b2
Keyboard.00b3
Keyboard.00b4
Keyboard.00b5
Keyboard.00b6
Keyboard.00b7
Keyboard.00b8
Keyboard.00b9
Keyboard.00ba
Keyboard.00bb
Keyboard.00bc
Keyboard.00bd
Keyboard.00be
Keyboard.00bf
Keyboard.00c0
Keyboard.00c1
Keyboard.00c2
Keyboard.00c3
Keyboard.00c4
Keyboard.00c5
Keyboard.00c6
Keyboard.00c7
Keyboard.00c8
Keyboard.00c9
Keyboard.00ca
Keyboard.00cb
Keyboard.00cc
Keyboard.00cd
Keyboard.00ce
Keyboard.00cf
Keyboard.00d0
Keyboard.00d1
Keyboard.00d2
Keyboard.00d3
Keyboard.00d4
Keyboard.00d5
Keyboard.00d6
Keyboard.00d7
Keyboard.00d8
Keyboard.00d9
Keyboard.00da
Keyboard.00db
Keyboard.00dc
Keyboard.00dd
Keyboard.00de
Keyboard.00df
Keyboard.00e0
Keyboard.00e1
Keyboard.00e2
Keyboard.00e3
Keyboard.00e4
Keyboard.00e5
Keyboard.00e6
Keyboard.00e7
Keyboard.00e8
Keyboard.00e9
Keyboard.00ea
Keyboard.00eb
Keyboard.00ec
Keyboard.00ed
Keyboard.00ee
Keyboard.00ef
Keyboard.00f0
Keyboard.00f1
Keyboard.00f2
Keyboard.00f3
Keyboard.00f4
Keyboard.00f5
Keyboard.00f6
Keyboard.00f7
Keyboard.00f8
Keyboard.00f9
Keyboard.00fa
Keyboard.00fb
Keyboard.00fc
Keyboard.00fd
Keyboard.00fe
Keyboard.00ff
Logical Minimum(0)
Logical Maximum(255)
Report Size(8)
Report Count(6)
Report Offset(16)
Flags( Array Absolute )
OUTPUT[OUTPUT]
Field(0)
Application(GenericDesktop.Keyboard)
Usage(5)
LED.NumLock
LED.CapsLock
LED.ScrollLock
LED.Compose
LED.Kana
Logical Minimum(0)
Logical Maximum(1)
Report Size(1)
Report Count(5)
Report Offset(0)
Flags( Variable Absolute )
Keyboard.00e0 ---> Key.LeftControl
Keyboard.00e1 ---> Key.LeftShift
Keyboard.00e2 ---> Key.LeftAlt
Keyboard.00e3 ---> Key.LeftMeta
Keyboard.00e4 ---> Key.RightCtrl
Keyboard.00e5 ---> Key.RightShift
Keyboard.00e6 ---> Key.RightAlt
Keyboard.00e7 ---> Key.RightMeta
Keyboard.0000 ---> Sync.Report
Keyboard.0001 ---> Sync.Report
Keyboard.0002 ---> Sync.Report
Keyboard.0003 ---> Sync.Report
Keyboard.0004 ---> Key.A
Keyboard.0005 ---> Key.B
Keyboard.0006 ---> Key.C
Keyboard.0007 ---> Key.D
Keyboard.0008 ---> Key.E
Keyboard.0009 ---> Key.F
Keyboard.000a ---> Key.G
Keyboard.000b ---> Key.H
Keyboard.000c ---> Key.I
Keyboard.000d ---> Key.J
Keyboard.000e ---> Key.K
Keyboard.000f ---> Key.L
Keyboard.0010 ---> Key.M
Keyboard.0011 ---> Key.N
Keyboard.0012 ---> Key.O
Keyboard.0013 ---> Key.P
Keyboard.0014 ---> Key.Q
Keyboard.0015 ---> Key.R
Keyboard.0016 ---> Key.S
Keyboard.0017 ---> Key.T
Keyboard.0018 ---> Key.U
Keyboard.0019 ---> Key.V
Keyboard.001a ---> Key.W
Keyboard.001b ---> Key.X
Keyboard.001c ---> Key.Y
Keyboard.001d ---> Key.Z
Keyboard.001e ---> Key.1
Keyboard.001f ---> Key.2
Keyboard.0020 ---> Key.3
Keyboard.0021 ---> Key.4
Keyboard.0022 ---> Key.5
Keyboard.0023 ---> Key.6
Keyboard.0024 ---> Key.7
Keyboard.0025 ---> Key.8
Keyboard.0026 ---> Key.9
Keyboard.0027 ---> Key.0
Keyboard.0028 ---> Key.Enter
Keyboard.0029 ---> Key.Esc
Keyboard.002a ---> Key.Backspace
Keyboard.002b ---> Key.Tab
Keyboard.002c ---> Key.Space
Keyboard.002d ---> Key.Minus
Keyboard.002e ---> Key.Equal
Keyboard.002f ---> Key.LeftBrace
Keyboard.0030 ---> Key.RightBrace
Keyboard.0031 ---> Key.BackSlash
Keyboard.0032 ---> Key.BackSlash
Keyboard.0033 ---> Key.Semicolon
Keyboard.0034 ---> Key.Apostrophe
Keyboard.0035 ---> Key.Grave
Keyboard.0036 ---> Key.Comma
Keyboard.0037 ---> Key.Dot
Keyboard.0038 ---> Key.Slash
Keyboard.0039 ---> Key.CapsLock
Keyboard.003a ---> Key.F1
Keyboard.003b ---> Key.F2
Keyboard.003c ---> Key.F3
Keyboard.003d ---> Key.F4
Keyboard.003e ---> Key.F5
Keyboard.003f ---> Key.F6
Keyboard.0040 ---> Key.F7
Keyboard.0041 ---> Key.F8
Keyboard.0042 ---> Key.F9
Keyboard.0043 ---> Key.F10
Keyboard.0044 ---> Key.F11
Keyboard.0045 ---> Key.F12
Keyboard.0046 ---> Key.SysRq
Keyboard.0047 ---> Key.ScrollLock
Keyboard.0048 ---> Key.Pause
Keyboard.0049 ---> Key.Insert
Keyboard.004a ---> Key.Home
Keyboard.004b ---> Key.PageUp
Keyboard.004c ---> Key.Delete
Keyboard.004d ---> Key.End
Keyboard.004e ---> Key.PageDown
Keyboard.004f ---> Key.Right
Keyboard.0050 ---> Key.Left
Keyboard.0051 ---> Key.Down
Keyboard.0052 ---> Key.Up
Keyboard.0053 ---> Key.NumLock
Keyboard.0054 ---> Key.KPSlash
Keyboard.0055 ---> Key.KPAsterisk
Keyboard.0056 ---> Key.KPMinus
Keyboard.0057 ---> Key.KPPlus
Keyboard.0058 ---> Key.KPEnter
Keyboard.0059 ---> Key.KP1
Keyboard.005a ---> Key.KP2
Keyboard.005b ---> Key.KP3
Keyboard.005c ---> Key.KP4
Keyboard.005d ---> Key.KP5
Keyboard.005e ---> Key.KP6
Keyboard.005f ---> Key.KP7
Keyboard.0060 ---> Key.KP8
Keyboard.0061 ---> Key.KP9
Keyboard.0062 ---> Key.KP0
Keyboard.0063 ---> Key.KPDot
Keyboard.0064 ---> Key.102nd
Keyboard.0065 ---> Key.Compose
Keyboard.0066 ---> Key.Power
Keyboard.0067 ---> Key.KPEqual
Keyboard.0068 ---> Key.F13
Keyboard.0069 ---> Key.F14
Keyboard.006a ---> Key.F15
Keyboard.006b ---> Key.F16
Keyboard.006c ---> Key.F17
Keyboard.006d ---> Key.F18
Keyboard.006e ---> Key.F19
Keyboard.006f ---> Key.F20
Keyboard.0070 ---> Key.F21
Keyboard.0071 ---> Key.F22
Keyboard.0072 ---> Key.F23
Keyboard.0073 ---> Key.F24
Keyboard.0074 ---> Key.Open
Keyboard.0075 ---> Key.Help
Keyboard.0076 ---> Key.Props
Keyboard.0077 ---> Key.Front
Keyboard.0078 ---> Key.Stop
Keyboard.0079 ---> Key.Again
Keyboard.007a ---> Key.Undo
Keyboard.007b ---> Key.Cut
Keyboard.007c ---> Key.Copy
Keyboard.007d ---> Key.Paste
Keyboard.007e ---> Key.Find
Keyboard.007f ---> Key.Mute
Keyboard.0080 ---> Key.VolumeUp
Keyboard.0081 ---> Key.VolumeDown
Keyboard.0082 ---> Key.Unknown
Keyboard.0083 ---> Key.Unknown
Keyboard.0084 ---> Key.Unknown
Keyboard.0085 ---> Key.KPComma
Keyboard.0086 ---> Key.Unknown
Keyboard.0087 ---> Key.RO
Keyboard.0088 ---> Key.Katakana/Hiragana
Keyboard.0089 ---> Key.Yen
Keyboard.008a ---> Key.Henkan
Keyboard.008b ---> Key.Muhenkan
Keyboard.008c ---> Key.KPJpComma
Keyboard.008d ---> Key.Unknown
Keyboard.008e ---> Key.Unknown
Keyboard.008f ---> Key.Unknown
Keyboard.0090 ---> Key.Hangeul
Keyboard.0091 ---> Key.Hanja
Keyboard.0092 ---> Key.Katakana
Keyboard.0093 ---> Key.HIRAGANA
Keyboard.0094 ---> Key.Zenkaku/Hankaku
Keyboard.0095 ---> Key.Unknown
Keyboard.0096 ---> Key.Unknown
Keyboard.0097 ---> Key.Unknown
Keyboard.0098 ---> Key.Unknown
Keyboard.0099 ---> Key.Unknown
Keyboard.009a ---> Key.Unknown
Keyboard.009b ---> Key.Unknown
Keyboard.009c ---> Key.Delete
Keyboard.009d ---> Key.Unknown
Keyboard.009e ---> Key.Unknown
Keyboard.009f ---> Key.Unknown
Keyboard.00a0 ---> Key.Unknown
Keyboard.00a1 ---> Key.Unknown
Keyboard.00a2 ---> Key.Unknown
Keyboard.00a3 ---> Key.Unknown
Keyboard.00a4 ---> Key.Unknown
Keyboard.00a5 ---> Key.Unknown
Keyboard.00a6 ---> Key.Unknown
Keyboard.00a7 ---> Key.Unknown
Keyboard.00a8 ---> Key.Unknown
Keyboard.00a9 ---> Key.Unknown
Keyboard.00aa ---> Key.Unknown
Keyboard.00ab ---> Key.Unknown
Keyboard.00ac ---> Key.Unknown
Keyboard.00ad ---> Key.Unknown
Keyboard.00ae ---> Key.Unknown
Keyboard.00af ---> Key.Unknown
Keyboard.00b0 ---> Key.Unknown
Keyboard.00b1 ---> Key.Unknown
Keyboard.00b2 ---> Key.Unknown
Keyboard.00b3 ---> Key.Unknown
Keyboard.00b4 ---> Key.Unknown
Keyboard.00b5 ---> Key.Unknown
Keyboard.00b6 ---> Key.KPLeftParenthesis
Keyboard.00b7 ---> Key.KPRightParenthesis
Keyboard.00b8 ---> Key.Unknown
Keyboard.00b9 ---> Key.Unknown
Keyboard.00ba ---> Key.Unknown
Keyboard.00bb ---> Key.Unknown
Keyboard.00bc ---> Key.Unknown
Keyboard.00bd ---> Key.Unknown
Keyboard.00be ---> Key.Unknown
Keyboard.00bf ---> Key.Unknown
Keyboard.00c0 ---> Key.Unknown
Keyboard.00c1 ---> Key.Unknown
Keyboard.00c2 ---> Key.Unknown
Keyboard.00c3 ---> Key.Unknown
Keyboard.00c4 ---> Key.Unknown
Keyboard.00c5 ---> Key.Unknown
Keyboard.00c6 ---> Key.Unknown
Keyboard.00c7 ---> Key.Unknown
Keyboard.00c8 ---> Key.Unknown
Keyboard.00c9 ---> Key.Unknown
Keyboard.00ca ---> Key.Unknown
Keyboard.00cb ---> Key.Unknown
Keyboard.00cc ---> Key.Unknown
Keyboard.00cd ---> Key.Unknown
Keyboard.00ce ---> Key.Unknown
Keyboard.00cf ---> Key.Unknown
Keyboard.00d0 ---> Key.Unknown
Keyboard.00d1 ---> Key.Unknown
Keyboard.00d2 ---> Key.Unknown
Keyboard.00d3 ---> Key.Unknown
Keyboard.00d4 ---> Key.Unknown
Keyboard.00d5 ---> Key.Unknown
Keyboard.00d6 ---> Key.Unknown
Keyboard.00d7 ---> Key.Unknown
Keyboard.00d8 ---> Key.Delete
Keyboard.00d9 ---> Key.Unknown
Keyboard.00da ---> Key.Unknown
Keyboard.00db ---> Key.Unknown
Keyboard.00dc ---> Key.Unknown
Keyboard.00dd ---> Key.Unknown
Keyboard.00de ---> Key.Unknown
Keyboard.00df ---> Key.Unknown
Keyboard.00e0 ---> Key.LeftControl
Keyboard.00e1 ---> Key.LeftShift
Keyboard.00e2 ---> Key.LeftAlt
Keyboard.00e3 ---> Key.LeftMeta
Keyboard.00e4 ---> Key.RightCtrl
Keyboard.00e5 ---> Key.RightShift
Keyboard.00e6 ---> Key.RightAlt
Keyboard.00e7 ---> Key.RightMeta
Keyboard.00e8 ---> Key.PlayPause
Keyboard.00e9 ---> Key.StopCD
Keyboard.00ea ---> Key.PreviousSong
Keyboard.00eb ---> Key.NextSong
Keyboard.00ec ---> Key.EjectCD
Keyboard.00ed ---> Key.VolumeUp
Keyboard.00ee ---> Key.VolumeDown
Keyboard.00ef ---> Key.Mute
Keyboard.00f0 ---> Key.WWW
Keyboard.00f1 ---> Key.Back
Keyboard.00f2 ---> Key.Forward
Keyboard.00f3 ---> Key.Stop
Keyboard.00f4 ---> Key.Find
Keyboard.00f5 ---> Key.ScrollUp
Keyboard.00f6 ---> Key.ScrollDown
Keyboard.00f7 ---> Key.Edit
Keyboard.00f8 ---> Key.Sleep
Keyboard.00f9 ---> Key.Coffee
Keyboard.00fa ---> Key.Refresh
Keyboard.00fb ---> Key.Calc
Keyboard.00fc ---> Key.Unknown
Keyboard.00fd ---> Key.Unknown
Keyboard.00fe ---> Key.Unknown
Keyboard.00ff ---> Key.Unknown
LED.NumLock ---> LED.NumLock
LED.CapsLock ---> LED.CapsLock
LED.ScrollLock ---> LED.ScrollLock
LED.Compose ---> LED.Compose
LED.Kana ---> LED.Kana
根据我的理解如何解析它是 1+6 字节 = 7 字节，对吗？
然后我还制作了一个小应用程序，它从键盘的 /dev/hidraw1 读取数据，并且看到它总是读取 8 个字节！
是不是我错误地解析了报告描述符？
谢谢，然然