search

libusb / hidapi

A Simple cross-platform library for communicating with HID devices
https://libusb.info/hidapi/
Other
1.69k stars 398 forks source link

`hid_get_report_descriptor`: missing unnumbered feature report #703

Closed SuibianP closed 4 weeks ago

SuibianP commented 1 month ago

On some devices, unnumbered feature reports seem omitted from the parsed HIDP_PREPARSED_DATA. The hid_pp_caps_info header indicates the count and size correctly, but marks it empty/unused.

# Feature caps_info struct:
pp_data->caps_info[2]->FirstCap           = 5
pp_data->caps_info[2]->LastCap            = 5
pp_data->caps_info[2]->NumberOfCaps       = 1
pp_data->caps_info[2]->ReportByteLength   = 91
# Output hid_pp_cap struct:
# Feature hid_pp_cap struct:
# Link Collections:

https://github.com/libusb/hidapi/blob/750bf201ae906eec1dc52c97087c8d0104c091ae/windows/hidapi_descriptor_reconstruct.h#L109-L114

If I anyhow print the trailing phid_pp_cap out, it consists entirely of zeros.

This is likely an existing bug/undocumented aspect of HidD_GetPreparsedData on MS side, and I am unsure if it could be worked around in userspace.

HID report descriptor (dumped on Linux with hid-decode) ```c # device 0:0 # 0x05, 0x01, // Usage Page (Generic Desktop) 0 # 0x09, 0x02, // Usage (Mouse) 2 # 0xa1, 0x01, // Collection (Application) 4 # 0x09, 0x01, // Usage (Pointer) 6 # 0xa1, 0x00, // Collection (Physical) 8 # 0x05, 0x09, // Usage Page (Button) 10 # 0x19, 0x01, // Usage Minimum (1) 12 # 0x29, 0x05, // Usage Maximum (5) 14 # 0x15, 0x00, // Logical Minimum (0) 16 # 0x25, 0x01, // Logical Maximum (1) 18 # 0x75, 0x01, // Report Size (1) 20 # 0x95, 0x05, // Report Count (5) 22 # 0x81, 0x02, // Input (Data,Var,Abs) 24 # 0x75, 0x01, // Report Size (1) 26 # 0x95, 0x03, // Report Count (3) 28 # 0x81, 0x03, // Input (Cnst,Var,Abs) 30 # 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 32 # 0x09, 0x40, // Usage (Vendor Usage 0x40) 35 # 0x75, 0x08, // Report Size (8) 37 # 0x95, 0x02, // Report Count (2) 39 # 0x15, 0x81, // Logical Minimum (-127) 41 # 0x25, 0x7f, // Logical Maximum (127) 43 # 0x81, 0x02, // Input (Data,Var,Abs) 45 # 0x05, 0x01, // Usage Page (Generic Desktop) 47 # 0x09, 0x38, // Usage (Wheel) 49 # 0x15, 0x81, // Logical Minimum (-127) 51 # 0x25, 0x7f, // Logical Maximum (127) 53 # 0x75, 0x08, // Report Size (8) 55 # 0x95, 0x01, // Report Count (1) 57 # 0x81, 0x06, // Input (Data,Var,Rel) 59 # 0x09, 0x30, // Usage (X) 61 # 0x09, 0x31, // Usage (Y) 63 # 0x16, 0x00, 0x80, // Logical Minimum (-32768) 65 # 0x26, 0xff, 0x7f, // Logical Maximum (32767) 68 # 0x75, 0x10, // Report Size (16) 71 # 0x95, 0x02, // Report Count (2) 73 # 0x81, 0x06, // Input (Data,Var,Rel) 75 # 0xc0, // End Collection 77 # 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 78 # 0x09, 0x02, // Usage (Vendor Usage 2) 81 # 0x15, 0x00, // Logical Minimum (0) 83 # 0x25, 0x01, // Logical Maximum (1) 85 # 0x75, 0x08, // Report Size (8) 87 # 0x95, 0x5a, // Report Count (90) 89 # 0xb1, 0x01, // Feature (Cnst,Arr,Abs) 91 # 0xc0, // End Collection 93 # R: 94 05 01 09 02 a1 01 09 01 a1 00 05 09 19 01 29 05 15 00 25 01 75 01 95 05 81 02 75 01 95 03 81 03 06 00 ff 09 40 75 08 95 02 15 81 25 7f 81 02 05 01 09 38 15 81 25 7f 75 08 95 01 81 06 09 30 09 31 16 00 80 26 ff 7f 75 10 95 02 81 06 c0 06 00 ff 09 02 15 00 25 01 75 08 95 5a b1 01 c0 N: device 0:0 I: 3 0001 0001 # device 1:0 # 0x05, 0x01, // Usage Page (Generic Desktop) 0 # 0x09, 0x06, // Usage (Keyboard) 2 # 0xa1, 0x01, // Collection (Application) 4 # 0x85, 0x01, // Report ID (1) 6 # 0x05, 0x07, // Usage Page (Keyboard) 8 # 0x19, 0xe0, // Usage Minimum (224) 10 # 0x29, 0xe7, // Usage Maximum (231) 12 # 0x15, 0x00, // Logical Minimum (0) 14 # 0x25, 0x01, // Logical Maximum (1) 16 # 0x75, 0x01, // Report Size (1) 18 # 0x95, 0x08, // Report Count (8) 20 # 0x81, 0x02, // Input (Data,Var,Abs) 22 # 0x19, 0x00, // Usage Minimum (0) 24 # 0x2a, 0xff, 0x00, // Usage Maximum (255) 26 # 0x15, 0x00, // Logical Minimum (0) 29 # 0x26, 0xff, 0x00, // Logical Maximum (255) 31 # 0x75, 0x08, // Report Size (8) 34 # 0x95, 0x0e, // Report Count (14) 36 # 0x81, 0x00, // Input (Data,Arr,Abs) 38 # 0xc0, // End Collection 40 # 0x05, 0x0c, // Usage Page (Consumer Devices) 41 # 0x09, 0x01, // Usage (Consumer Control) 43 # 0xa1, 0x01, // Collection (Application) 45 # 0x85, 0x02, // Report ID (2) 47 # 0x19, 0x00, // Usage Minimum (0) 49 # 0x2a, 0x3c, 0x02, // Usage Maximum (572) 51 # 0x15, 0x00, // Logical Minimum (0) 54 # 0x26, 0x3c, 0x02, // Logical Maximum (572) 56 # 0x95, 0x01, // Report Count (1) 59 # 0x75, 0x10, // Report Size (16) 61 # 0x81, 0x00, // Input (Data,Arr,Abs) 63 # 0x75, 0x08, // Report Size (8) 65 # 0x95, 0x0d, // Report Count (13) 67 # 0x81, 0x01, // Input (Cnst,Arr,Abs) 69 # 0xc0, // End Collection 71 # 0x05, 0x01, // Usage Page (Generic Desktop) 72 # 0x09, 0x80, // Usage (System Control) 74 # 0xa1, 0x01, // Collection (Application) 76 # 0x85, 0x03, // Report ID (3) 78 # 0x19, 0x81, // Usage Minimum (129) 80 # 0x29, 0x83, // Usage Maximum (131) 82 # 0x15, 0x00, // Logical Minimum (0) 84 # 0x25, 0x01, // Logical Maximum (1) 86 # 0x75, 0x01, // Report Size (1) 88 # 0x95, 0x03, // Report Count (3) 90 # 0x81, 0x02, // Input (Data,Var,Abs) 92 # 0x95, 0x05, // Report Count (5) 94 # 0x81, 0x01, // Input (Cnst,Arr,Abs) 96 # 0x75, 0x08, // Report Size (8) 98 # 0x95, 0x0e, // Report Count (14) 100 # 0x81, 0x01, // Input (Cnst,Arr,Abs) 102 # 0xc0, // End Collection 104 # 0x05, 0x01, // Usage Page (Generic Desktop) 105 # 0x09, 0x00, // Usage (Undefined) 107 # 0xa1, 0x01, // Collection (Application) 109 # 0x85, 0x04, // Report ID (4) 111 # 0x09, 0x03, // Usage (Vendor Usage 0x03) 113 # 0x15, 0x00, // Logical Minimum (0) 115 # 0x26, 0xff, 0x00, // Logical Maximum (255) 117 # 0x35, 0x00, // Physical Minimum (0) 120 # 0x46, 0xff, 0x00, // Physical Maximum (255) 122 # 0x75, 0x08, // Report Size (8) 125 # 0x95, 0x0f, // Report Count (15) 127 # 0x81, 0x00, // Input (Data,Arr,Abs) 129 # 0xc0, // End Collection 131 # 0x05, 0x01, // Usage Page (Generic Desktop) 132 # 0x09, 0x00, // Usage (Undefined) 134 # 0xa1, 0x01, // Collection (Application) 136 # 0x85, 0x05, // Report ID (5) 138 # 0x09, 0x03, // Usage (Vendor Usage 0x03) 140 # 0x15, 0x00, // Logical Minimum (0) 142 # 0x26, 0xff, 0x00, // Logical Maximum (255) 144 # 0x35, 0x00, // Physical Minimum (0) 147 # 0x46, 0xff, 0x00, // Physical Maximum (255) 149 # 0x75, 0x08, // Report Size (8) 152 # 0x95, 0x0f, // Report Count (15) 154 # 0x81, 0x00, // Input (Data,Arr,Abs) 156 # 0xc0, // End Collection 158 # R: 159 05 01 09 06 a1 01 85 01 05 07 19 e0 29 e7 15 00 25 01 75 01 95 08 81 02 19 00 2a ff 00 15 00 26 ff 00 75 08 95 0e 81 00 c0 05 0c 09 01 a1 01 85 02 19 00 2a 3c 02 15 00 26 3c 02 95 01 75 10 81 00 75 08 95 0d 81 01 c0 05 01 09 80 a1 01 85 03 19 81 29 83 15 00 25 01 75 01 95 03 81 02 95 05 81 01 75 08 95 0e 81 01 c0 05 01 09 00 a1 01 85 04 09 03 15 00 26 ff 00 35 00 46 ff 00 75 08 95 0f 81 00 c0 05 01 09 00 a1 01 85 05 09 03 15 00 26 ff 00 35 00 46 ff 00 75 08 95 0f 81 00 c0 N: device 1:0 I: 3 0001 0001 # device 2:0 # 0x05, 0x01, // Usage Page (Generic Desktop) 0 # 0x09, 0x06, // Usage (Keyboard) 2 # 0xa1, 0x01, // Collection (Application) 4 # 0x05, 0x07, // Usage Page (Keyboard) 6 # 0x19, 0xe0, // Usage Minimum (224) 8 # 0x29, 0xe7, // Usage Maximum (231) 10 # 0x15, 0x00, // Logical Minimum (0) 12 # 0x25, 0x01, // Logical Maximum (1) 14 # 0x75, 0x01, // Report Size (1) 16 # 0x95, 0x08, // Report Count (8) 18 # 0x81, 0x02, // Input (Data,Var,Abs) 20 # 0x81, 0x01, // Input (Cnst,Arr,Abs) 22 # 0x19, 0x00, // Usage Minimum (0) 24 # 0x2a, 0xff, 0x00, // Usage Maximum (255) 26 # 0x15, 0x00, // Logical Minimum (0) 29 # 0x26, 0xff, 0x00, // Logical Maximum (255) 31 # 0x75, 0x08, // Report Size (8) 34 # 0x95, 0x06, // Report Count (6) 36 # 0x81, 0x00, // Input (Data,Arr,Abs) 38 # 0x05, 0x08, // Usage Page (LEDs) 40 # 0x19, 0x01, // Usage Minimum (1) 42 # 0x29, 0x03, // Usage Maximum (3) 44 # 0x15, 0x00, // Logical Minimum (0) 46 # 0x25, 0x01, // Logical Maximum (1) 48 # 0x75, 0x01, // Report Size (1) 50 # 0x95, 0x03, // Report Count (3) 52 # 0x91, 0x02, // Output (Data,Var,Abs) 54 # 0x95, 0x05, // Report Count (5) 56 # 0x91, 0x01, // Output (Cnst,Arr,Abs) 58 # 0xc0, // End Collection 60 # R: 61 05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 75 01 95 08 81 02 81 01 19 00 2a ff 00 15 00 26 ff 00 75 08 95 06 81 00 05 08 19 01 29 03 15 00 25 01 75 01 95 03 91 02 95 05 91 01 c0 N: device 2:0 I: 3 0001 0001 ```
Full 1532_00A3_0002_0001.pp_data ```pike # HIDAPI device info struct: dev->vendor_id = 0x1532 dev->product_id = 0x00A3 dev->manufacturer_string = "Razer" dev->product_string = "Razer Cobra" dev->release_number = 0x0200 dev->interface_number = 0 dev->usage = 0x0002 dev->usage_page = 0x0001 dev->path = "\\?\HID#VID_1532&PID_00A3&MI_00#7&370ad372&0&0000#{4d1e55b2-f16f-11cf-88cb-001111000030}" # Preparsed Data struct: pp_data->MagicKey = 0x48696450204B4452 pp_data->Usage = 0x0002 pp_data->UsagePage = 0x0001 pp_data->Reserved = 0x00000000 # Input caps_info struct: pp_data->caps_info[0]->FirstCap = 0 pp_data->caps_info[0]->LastCap = 5 pp_data->caps_info[0]->NumberOfCaps = 5 pp_data->caps_info[0]->ReportByteLength = 9 # Output caps_info struct: pp_data->caps_info[1]->FirstCap = 5 pp_data->caps_info[1]->LastCap = 5 pp_data->caps_info[1]->NumberOfCaps = 0 pp_data->caps_info[1]->ReportByteLength = 0 # Feature caps_info struct: pp_data->caps_info[2]->FirstCap = 5 pp_data->caps_info[2]->LastCap = 5 pp_data->caps_info[2]->NumberOfCaps = 1 pp_data->caps_info[2]->ReportByteLength = 91 # LinkCollectionArray Offset & Size: pp_data->FirstByteOfLinkCollectionArray = 0x0270 pp_data->NumberLinkCollectionNodes = 2 # Input hid_pp_cap struct: pp_data->cap[0]->UsagePage = 0x0009 pp_data->cap[0]->ReportID = 0x00 pp_data->cap[0]->BitPosition = 0 pp_data->cap[0]->BitSize = 1 pp_data->cap[0]->ReportCount = 5 pp_data->cap[0]->BytePosition = 0x0001 pp_data->cap[0]->BitCount = 5 pp_data->cap[0]->BitField = 0x02 pp_data->cap[0]->NextBytePosition = 0x0002 pp_data->cap[0]->LinkCollection = 0x0001 pp_data->cap[0]->LinkUsagePage = 0x0001 pp_data->cap[0]->LinkUsage = 0x0001 pp_data->cap[0]->IsMultipleItemsForArray = 0 pp_data->cap[0]->IsButtonCap = 1 pp_data->cap[0]->IsPadding = 0 pp_data->cap[0]->IsAbsolute = 1 pp_data->cap[0]->IsRange = 1 pp_data->cap[0]->IsAlias = 0 pp_data->cap[0]->IsStringRange = 0 pp_data->cap[0]->IsDesignatorRange = 0 pp_data->cap[0]->Reserved1 = 0x000000 pp_data->cap[0]->pp_cap->UnknownTokens[0].Token = 0x00 pp_data->cap[0]->pp_cap->UnknownTokens[0].Reserved = 0x000000 pp_data->cap[0]->pp_cap->UnknownTokens[0].BitField = 0x00000000 pp_data->cap[0]->pp_cap->UnknownTokens[1].Token = 0x00 pp_data->cap[0]->pp_cap->UnknownTokens[1].Reserved = 0x000000 pp_data->cap[0]->pp_cap->UnknownTokens[1].BitField = 0x00000000 pp_data->cap[0]->pp_cap->UnknownTokens[2].Token = 0x00 pp_data->cap[0]->pp_cap->UnknownTokens[2].Reserved = 0x000000 pp_data->cap[0]->pp_cap->UnknownTokens[2].BitField = 0x00000000 pp_data->cap[0]->pp_cap->UnknownTokens[3].Token = 0x00 pp_data->cap[0]->pp_cap->UnknownTokens[3].Reserved = 0x000000 pp_data->cap[0]->pp_cap->UnknownTokens[3].BitField = 0x00000000 pp_data->cap[0]->Range.UsageMin = 0x0001 pp_data->cap[0]->Range.UsageMax = 0x0005 pp_data->cap[0]->Range.StringMin = 0 pp_data->cap[0]->Range.StringMax = 0 pp_data->cap[0]->Range.DesignatorMin = 0 pp_data->cap[0]->Range.DesignatorMax = 0 pp_data->cap[0]->Range.DataIndexMin = 0 pp_data->cap[0]->Range.DataIndexMax = 4 pp_data->cap[0]->Button.LogicalMin = 0 pp_data->cap[0]->Button.LogicalMax = 0 pp_data->cap[0]->Units = 0 pp_data->cap[0]->UnitsExp = 0 pp_data->cap[1]->UsagePage = 0xFF00 pp_data->cap[1]->ReportID = 0x00 pp_data->cap[1]->BitPosition = 0 pp_data->cap[1]->BitSize = 8 pp_data->cap[1]->ReportCount = 2 pp_data->cap[1]->BytePosition = 0x0002 pp_data->cap[1]->BitCount = 16 pp_data->cap[1]->BitField = 0x02 pp_data->cap[1]->NextBytePosition = 0x0004 pp_data->cap[1]->LinkCollection = 0x0001 pp_data->cap[1]->LinkUsagePage = 0x0001 pp_data->cap[1]->LinkUsage = 0x0001 pp_data->cap[1]->IsMultipleItemsForArray = 0 pp_data->cap[1]->IsButtonCap = 0 pp_data->cap[1]->IsPadding = 0 pp_data->cap[1]->IsAbsolute = 1 pp_data->cap[1]->IsRange = 0 pp_data->cap[1]->IsAlias = 0 pp_data->cap[1]->IsStringRange = 0 pp_data->cap[1]->IsDesignatorRange = 0 pp_data->cap[1]->Reserved1 = 0x000000 pp_data->cap[1]->pp_cap->UnknownTokens[0].Token = 0x00 pp_data->cap[1]->pp_cap->UnknownTokens[0].Reserved = 0x000000 pp_data->cap[1]->pp_cap->UnknownTokens[0].BitField = 0x00000000 pp_data->cap[1]->pp_cap->UnknownTokens[1].Token = 0x00 pp_data->cap[1]->pp_cap->UnknownTokens[1].Reserved = 0x000000 pp_data->cap[1]->pp_cap->UnknownTokens[1].BitField = 0x00000000 pp_data->cap[1]->pp_cap->UnknownTokens[2].Token = 0x00 pp_data->cap[1]->pp_cap->UnknownTokens[2].Reserved = 0x000000 pp_data->cap[1]->pp_cap->UnknownTokens[2].BitField = 0x00000000 pp_data->cap[1]->pp_cap->UnknownTokens[3].Token = 0x00 pp_data->cap[1]->pp_cap->UnknownTokens[3].Reserved = 0x000000 pp_data->cap[1]->pp_cap->UnknownTokens[3].BitField = 0x00000000 pp_data->cap[1]->NotRange.Usage = 0x0040 pp_data->cap[1]->NotRange.Reserved1 = 0x0040 pp_data->cap[1]->NotRange.StringIndex = 0 pp_data->cap[1]->NotRange.Reserved2 = 0 pp_data->cap[1]->NotRange.DesignatorIndex = 0 pp_data->cap[1]->NotRange.Reserved3 = 0 pp_data->cap[1]->NotRange.DataIndex = 5 pp_data->cap[1]->NotRange.Reserved4 = 5 pp_data->cap[1]->NotButton.HasNull = 0 pp_data->cap[1]->NotButton.Reserved4 = 0x000000 pp_data->cap[1]->NotButton.LogicalMin = -127 pp_data->cap[1]->NotButton.LogicalMax = 127 pp_data->cap[1]->NotButton.PhysicalMin = 0 pp_data->cap[1]->NotButton.PhysicalMax = 0 pp_data->cap[1]->Units = 0 pp_data->cap[1]->UnitsExp = 0 pp_data->cap[2]->UsagePage = 0x0001 pp_data->cap[2]->ReportID = 0x00 pp_data->cap[2]->BitPosition = 0 pp_data->cap[2]->BitSize = 8 pp_data->cap[2]->ReportCount = 1 pp_data->cap[2]->BytePosition = 0x0004 pp_data->cap[2]->BitCount = 8 pp_data->cap[2]->BitField = 0x06 pp_data->cap[2]->NextBytePosition = 0x0005 pp_data->cap[2]->LinkCollection = 0x0001 pp_data->cap[2]->LinkUsagePage = 0x0001 pp_data->cap[2]->LinkUsage = 0x0001 pp_data->cap[2]->IsMultipleItemsForArray = 0 pp_data->cap[2]->IsButtonCap = 0 pp_data->cap[2]->IsPadding = 0 pp_data->cap[2]->IsAbsolute = 0 pp_data->cap[2]->IsRange = 0 pp_data->cap[2]->IsAlias = 0 pp_data->cap[2]->IsStringRange = 0 pp_data->cap[2]->IsDesignatorRange = 0 pp_data->cap[2]->Reserved1 = 0x000000 pp_data->cap[2]->pp_cap->UnknownTokens[0].Token = 0x00 pp_data->cap[2]->pp_cap->UnknownTokens[0].Reserved = 0x000000 pp_data->cap[2]->pp_cap->UnknownTokens[0].BitField = 0x00000000 pp_data->cap[2]->pp_cap->UnknownTokens[1].Token = 0x00 pp_data->cap[2]->pp_cap->UnknownTokens[1].Reserved = 0x000000 pp_data->cap[2]->pp_cap->UnknownTokens[1].BitField = 0x00000000 pp_data->cap[2]->pp_cap->UnknownTokens[2].Token = 0x00 pp_data->cap[2]->pp_cap->UnknownTokens[2].Reserved = 0x000000 pp_data->cap[2]->pp_cap->UnknownTokens[2].BitField = 0x00000000 pp_data->cap[2]->pp_cap->UnknownTokens[3].Token = 0x00 pp_data->cap[2]->pp_cap->UnknownTokens[3].Reserved = 0x000000 pp_data->cap[2]->pp_cap->UnknownTokens[3].BitField = 0x00000000 pp_data->cap[2]->NotRange.Usage = 0x0038 pp_data->cap[2]->NotRange.Reserved1 = 0x0038 pp_data->cap[2]->NotRange.StringIndex = 0 pp_data->cap[2]->NotRange.Reserved2 = 0 pp_data->cap[2]->NotRange.DesignatorIndex = 0 pp_data->cap[2]->NotRange.Reserved3 = 0 pp_data->cap[2]->NotRange.DataIndex = 6 pp_data->cap[2]->NotRange.Reserved4 = 6 pp_data->cap[2]->NotButton.HasNull = 0 pp_data->cap[2]->NotButton.Reserved4 = 0x000000 pp_data->cap[2]->NotButton.LogicalMin = -127 pp_data->cap[2]->NotButton.LogicalMax = 127 pp_data->cap[2]->NotButton.PhysicalMin = 0 pp_data->cap[2]->NotButton.PhysicalMax = 0 pp_data->cap[2]->Units = 0 pp_data->cap[2]->UnitsExp = 0 pp_data->cap[3]->UsagePage = 0x0001 pp_data->cap[3]->ReportID = 0x00 pp_data->cap[3]->BitPosition = 0 pp_data->cap[3]->BitSize = 16 pp_data->cap[3]->ReportCount = 1 pp_data->cap[3]->BytePosition = 0x0007 pp_data->cap[3]->BitCount = 16 pp_data->cap[3]->BitField = 0x06 pp_data->cap[3]->NextBytePosition = 0x0009 pp_data->cap[3]->LinkCollection = 0x0001 pp_data->cap[3]->LinkUsagePage = 0x0001 pp_data->cap[3]->LinkUsage = 0x0001 pp_data->cap[3]->IsMultipleItemsForArray = 0 pp_data->cap[3]->IsButtonCap = 0 pp_data->cap[3]->IsPadding = 0 pp_data->cap[3]->IsAbsolute = 0 pp_data->cap[3]->IsRange = 0 pp_data->cap[3]->IsAlias = 0 pp_data->cap[3]->IsStringRange = 0 pp_data->cap[3]->IsDesignatorRange = 0 pp_data->cap[3]->Reserved1 = 0x000000 pp_data->cap[3]->pp_cap->UnknownTokens[0].Token = 0x00 pp_data->cap[3]->pp_cap->UnknownTokens[0].Reserved = 0x000000 pp_data->cap[3]->pp_cap->UnknownTokens[0].BitField = 0x00000000 pp_data->cap[3]->pp_cap->UnknownTokens[1].Token = 0x00 pp_data->cap[3]->pp_cap->UnknownTokens[1].Reserved = 0x000000 pp_data->cap[3]->pp_cap->UnknownTokens[1].BitField = 0x00000000 pp_data->cap[3]->pp_cap->UnknownTokens[2].Token = 0x00 pp_data->cap[3]->pp_cap->UnknownTokens[2].Reserved = 0x000000 pp_data->cap[3]->pp_cap->UnknownTokens[2].BitField = 0x00000000 pp_data->cap[3]->pp_cap->UnknownTokens[3].Token = 0x00 pp_data->cap[3]->pp_cap->UnknownTokens[3].Reserved = 0x000000 pp_data->cap[3]->pp_cap->UnknownTokens[3].BitField = 0x00000000 pp_data->cap[3]->NotRange.Usage = 0x0031 pp_data->cap[3]->NotRange.Reserved1 = 0x0031 pp_data->cap[3]->NotRange.StringIndex = 0 pp_data->cap[3]->NotRange.Reserved2 = 0 pp_data->cap[3]->NotRange.DesignatorIndex = 0 pp_data->cap[3]->NotRange.Reserved3 = 0 pp_data->cap[3]->NotRange.DataIndex = 7 pp_data->cap[3]->NotRange.Reserved4 = 7 pp_data->cap[3]->NotButton.HasNull = 0 pp_data->cap[3]->NotButton.Reserved4 = 0x000000 pp_data->cap[3]->NotButton.LogicalMin = -32768 pp_data->cap[3]->NotButton.LogicalMax = 32767 pp_data->cap[3]->NotButton.PhysicalMin = 0 pp_data->cap[3]->NotButton.PhysicalMax = 0 pp_data->cap[3]->Units = 0 pp_data->cap[3]->UnitsExp = 0 pp_data->cap[4]->UsagePage = 0x0001 pp_data->cap[4]->ReportID = 0x00 pp_data->cap[4]->BitPosition = 0 pp_data->cap[4]->BitSize = 16 pp_data->cap[4]->ReportCount = 1 pp_data->cap[4]->BytePosition = 0x0005 pp_data->cap[4]->BitCount = 16 pp_data->cap[4]->BitField = 0x06 pp_data->cap[4]->NextBytePosition = 0x0007 pp_data->cap[4]->LinkCollection = 0x0001 pp_data->cap[4]->LinkUsagePage = 0x0001 pp_data->cap[4]->LinkUsage = 0x0001 pp_data->cap[4]->IsMultipleItemsForArray = 0 pp_data->cap[4]->IsButtonCap = 0 pp_data->cap[4]->IsPadding = 0 pp_data->cap[4]->IsAbsolute = 0 pp_data->cap[4]->IsRange = 0 pp_data->cap[4]->IsAlias = 0 pp_data->cap[4]->IsStringRange = 0 pp_data->cap[4]->IsDesignatorRange = 0 pp_data->cap[4]->Reserved1 = 0x000000 pp_data->cap[4]->pp_cap->UnknownTokens[0].Token = 0x00 pp_data->cap[4]->pp_cap->UnknownTokens[0].Reserved = 0x000000 pp_data->cap[4]->pp_cap->UnknownTokens[0].BitField = 0x00000000 pp_data->cap[4]->pp_cap->UnknownTokens[1].Token = 0x00 pp_data->cap[4]->pp_cap->UnknownTokens[1].Reserved = 0x000000 pp_data->cap[4]->pp_cap->UnknownTokens[1].BitField = 0x00000000 pp_data->cap[4]->pp_cap->UnknownTokens[2].Token = 0x00 pp_data->cap[4]->pp_cap->UnknownTokens[2].Reserved = 0x000000 pp_data->cap[4]->pp_cap->UnknownTokens[2].BitField = 0x00000000 pp_data->cap[4]->pp_cap->UnknownTokens[3].Token = 0x00 pp_data->cap[4]->pp_cap->UnknownTokens[3].Reserved = 0x000000 pp_data->cap[4]->pp_cap->UnknownTokens[3].BitField = 0x00000000 pp_data->cap[4]->NotRange.Usage = 0x0030 pp_data->cap[4]->NotRange.Reserved1 = 0x0030 pp_data->cap[4]->NotRange.StringIndex = 0 pp_data->cap[4]->NotRange.Reserved2 = 0 pp_data->cap[4]->NotRange.DesignatorIndex = 0 pp_data->cap[4]->NotRange.Reserved3 = 0 pp_data->cap[4]->NotRange.DataIndex = 8 pp_data->cap[4]->NotRange.Reserved4 = 8 pp_data->cap[4]->NotButton.HasNull = 0 pp_data->cap[4]->NotButton.Reserved4 = 0x000000 pp_data->cap[4]->NotButton.LogicalMin = -32768 pp_data->cap[4]->NotButton.LogicalMax = 32767 pp_data->cap[4]->NotButton.PhysicalMin = 0 pp_data->cap[4]->NotButton.PhysicalMax = 0 pp_data->cap[4]->Units = 0 pp_data->cap[4]->UnitsExp = 0 # Output hid_pp_cap struct: # Feature hid_pp_cap struct: # Link Collections: pp_data->LinkCollectionArray[0]->LinkUsage = 0x0002 pp_data->LinkCollectionArray[0]->LinkUsagePage = 0x0001 pp_data->LinkCollectionArray[0]->Parent = 0 pp_data->LinkCollectionArray[0]->NumberOfChildren = 1 pp_data->LinkCollectionArray[0]->NextSibling = 0 pp_data->LinkCollectionArray[0]->FirstChild = 1 pp_data->LinkCollectionArray[0]->CollectionType = 1 pp_data->LinkCollectionArray[0]->IsAlias = 0 pp_data->LinkCollectionArray[0]->Reserved = 0x00000000 pp_data->LinkCollectionArray[1]->LinkUsage = 0x0001 pp_data->LinkCollectionArray[1]->LinkUsagePage = 0x0001 pp_data->LinkCollectionArray[1]->Parent = 0 pp_data->LinkCollectionArray[1]->NumberOfChildren = 0 pp_data->LinkCollectionArray[1]->NextSibling = 0 pp_data->LinkCollectionArray[1]->FirstChild = 0 pp_data->LinkCollectionArray[1]->CollectionType = 0 pp_data->LinkCollectionArray[1]->IsAlias = 0 pp_data->LinkCollectionArray[1]->Reserved = 0x00000000 ```
Full HIDP_PREPARSED_DATA ``` 48 69 64 50 20 4B 44 52 02 00 01 00 00 00 00 00 00 00 05 00 05 00 09 00 05 00 00 00 05 00 00 00 05 00 01 00 05 00 5B 00 70 02 02 00 09 00 00 00 01 00 05 00 01 00 05 00 02 00 00 00 02 00 01 00 01 00 01 00 1C 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 05 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF 00 00 08 00 02 00 02 00 10 00 02 00 00 00 04 00 01 00 01 00 01 00 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 40 00 40 00 00 00 00 00 00 00 00 00 05 00 05 00 00 00 00 00 81 FF FF FF 7F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 08 00 01 00 04 00 08 00 06 00 00 00 05 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 38 00 38 00 00 00 00 00 00 00 00 00 06 00 06 00 00 00 00 00 81 FF FF FF 7F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 10 00 01 00 07 00 10 00 06 00 00 00 09 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 31 00 31 00 00 00 00 00 00 00 00 00 07 00 07 00 00 00 00 00 00 80 FF FF FF 7F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 10 00 01 00 05 00 10 00 06 00 00 00 07 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 30 00 30 00 00 00 00 00 00 00 00 00 08 00 08 00 00 00 00 00 00 80 FF FF FF 7F 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 01 00 00 00 01 00 00 00 01 00 01 00 00 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 B6 A8 3A 4B F2 62 00 00 A0 D8 77 36 04 02 00 00 00 02 78 36 04 02 00 00 EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE EE FE 00 00 00 00 00 00 00 00 B4 A8 39 4A D7 62 00 34 E0 C3 78 36 04 02 00 00 90 92 78 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 98 00 00 00 00 00 00 00 25 05 00 00 FD FD FD FD 0C 01 00 00 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 09 00 00 00 00 00 00 00 5B 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 C0 92 78 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 14 01 00 00 00 00 00 00 90 C5 77 36 04 02 00 00 E8 03 00 00 00 00 00 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB EE FE EE FE 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE AF A8 39 51 D5 62 00 34 90 92 78 36 04 02 00 00 10 C6 77 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 48 00 00 00 00 00 00 00 27 05 00 00 FD FD FD FD 40 C6 77 36 04 02 00 00 32 15 A3 00 00 00 00 00 00 C7 77 36 04 02 00 00 00 02 00 00 00 00 00 00 70 C7 77 36 04 02 00 00 E0 C7 77 36 04 02 00 00 01 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB EE FE EE FE 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE A8 A8 39 56 CE 62 00 33 60 C5 77 36 04 02 00 00 D0 C6 77 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 59 00 00 00 00 00 00 00 28 05 00 00 FD FD FD FD 5C 5C 3F 5C 48 49 44 23 56 49 44 5F 31 35 33 32 26 50 49 44 5F 30 30 41 33 26 4D 49 5F 30 30 23 37 26 33 37 30 61 64 33 37 32 26 30 26 30 30 30 30 23 7B 34 64 31 65 35 35 62 32 2D 66 31 36 66 2D 31 31 63 66 2D 38 38 63 62 2D 30 30 31 31 31 31 30 30 30 30 33 30 7D 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB FE EE FE 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE A3 A8 39 5D C9 62 00 3A 10 C6 77 36 04 02 00 00 40 C7 77 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 02 00 00 00 00 00 00 00 2B 05 00 00 FD FD FD FD 00 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB EE FE EE FE EE FE EE FE EE FE 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE A3 A8 39 5D C2 62 00 30 D0 C6 77 36 04 02 00 00 B0 C7 77 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 0C 00 00 00 00 00 00 00 2C 05 00 00 FD FD FD FD 52 00 61 00 7A 00 65 00 72 00 00 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE AC A8 39 52 C2 62 00 34 40 C7 77 36 04 02 00 00 30 C8 77 36 04 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 18 00 00 00 00 00 00 00 2D 05 00 00 FD FD FD FD 52 00 61 00 7A 00 65 00 72 00 20 00 43 00 6F 00 62 00 72 00 61 00 00 00 FD FD FD FD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB EE FE EE FE 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EE FE EE FE EE FE EE FE A3 A9 39 5C CD 62 00 3C B0 C7 77 36 04 02 00 00 00 00 00 00 00 00 00 00 C8 C2 F5 E3 F9 7F 00 00 1B 00 00 00 02 00 00 00 00 10 00 00 00 00 00 00 32 05 00 00 FD FD FD FD 23 20 48 49 44 41 50 49 20 64 65 76 69 63 65 20 69 6E 66 6F 20 73 74 72 75 63 74 3A 0A 64 65 76 2D 3E 76 65 6E 64 6F 72 5F 69 64 20 20 20 20 20 20 20 20 20 20 20 3D 20 30 78 31 35 33 32 0A 64 65 76 2D 3E 70 72 6F 64 75 63 74 5F 69 64 20 20 20 20 20 20 20 20 20 20 3D 20 30 78 30 30 41 33 0A 64 65 76 2D 3E 6D 61 6E 75 66 61 63 74 75 72 65 72 5F 73 74 72 69 6E 67 20 3D 20 22 52 61 7A 65 72 22 0A 64 65 76 2D 3E 70 72 6F 64 75 63 74 5F 73 74 72 69 6E 67 20 20 20 20 20 20 3D 20 22 52 61 7A 65 72 20 43 6F 62 72 61 22 0A 64 65 76 2D 3E 72 65 6C 65 61 73 65 5F 6E 75 6D 62 65 72 20 20 20 20 20 20 3D 20 30 78 30 32 30 30 0A 64 65 76 2D 3E 69 6E 74 65 72 66 61 63 65 5F 6E 75 6D 62 65 72 20 20 20 20 3D 20 30 0A 64 65 76 2D 3E 75 73 61 67 65 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3D 20 30 78 30 30 30 32 0A 64 65 76 2D 3E 75 73 61 67 65 5F 70 61 67 65 20 20 20 20 20 20 20 20 20 20 3D 20 30 78 30 30 30 31 0A 64 65 76 2D 3E 70 61 74 68 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3D 20 22 5C 5C 3F 5C 48 49 44 23 56 49 44 5F 31 35 33 32 26 50 49 44 5F 30 30 41 33 26 4D 49 5F 30 30 23 37 26 33 37 30 61 64 33 37 32 26 30 26 30 30 30 30 23 7B 34 64 31 65 35 35 62 32 2D 66 31 36 66 2D 31 31 63 66 2D 38 38 63 62 2D 30 30 31 31 31 31 30 30 30 30 33 30 7D 22 0A 0A 23 20 50 72 65 70 61 72 73 65 64 20 44 61 74 61 20 73 74 72 75 63 74 3A 0A 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ``` (Followed by all `0x00` until `HID_API_MAX_REPORT_DESCRIPTOR_SIZE`)
JoergAtGithub commented 1 month ago

This is a known limitation of the reconstructor: All bits in the feature report are const, and Windows removes any information about const caps during the pre-parsing step. The reconstructor determines these const padding bits from the bit position of the next non-const cap, but this does not work for additional const bytes at the end of the report.

But your example shows that in this particular case there is the possibility, to improve this. While we have no information about additional const bytes for a particular report, Windows tells us the needed buffer size for input, output and feature reports. This is the size of the largest report + one byte. In case of devices that don't use ReportIDs, we know that there can be only one report of each type. So we could determine the number of additional const bytes at the end of the report from hid_pp_caps_info->ReportByteLength.

Youw commented 4 weeks ago

@SuibianP would you be able to check if #707 brings any improvement for your case?

SuibianP commented 4 weeks ago

@Youw Tried dumping from the device just now and hid_report_reconstructor_test adds the last const report correctly. Usage page and usage are gone for good as expected.

@JoergAtGithub Thanks for the implementation!