296 lines
15 KiB
C
296 lines
15 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2024 Benjamin Tissoires
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*/
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#include "vmlinux.h"
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#include "hid_bpf.h"
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#include "hid_bpf_helpers.h"
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#include <bpf/bpf_tracing.h>
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#define VID_HUION 0x256C
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#define PID_KAMVAS_PRO_19 0x006B
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#define NAME_KAMVAS_PRO_19 "HUION Huion Tablet_GT1902"
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#define TEST_PREFIX "uhid test "
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HID_BPF_CONFIG(
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HID_DEVICE(BUS_USB, HID_GROUP_MULTITOUCH_WIN_8, VID_HUION, PID_KAMVAS_PRO_19),
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);
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bool prev_was_out_of_range;
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bool in_eraser_mode;
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/*
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* We need to amend the report descriptor for the following:
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* - the second button is reported through Secondary Tip Switch instead of Secondary Barrel Switch
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* - the third button is reported through Invert, and we need some room to report it.
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*
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*/
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static const __u8 fixed_rdesc[] = {
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0x05, 0x0d, // Usage Page (Digitizers) 0
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0x09, 0x02, // Usage (Pen) 2
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0xa1, 0x01, // Collection (Application) 4
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0x85, 0x0a, // Report ID (10) 6
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0x09, 0x20, // Usage (Stylus) 8
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0xa1, 0x01, // Collection (Application) 10
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0x09, 0x42, // Usage (Tip Switch) 12
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0x09, 0x44, // Usage (Barrel Switch) 14
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0x09, 0x5a, // Usage (Secondary Barrel Switch) 16 /* changed from Secondary Tip Switch */
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0x09, 0x3c, // Usage (Invert) 18
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0x09, 0x45, // Usage (Eraser) 20
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0x15, 0x00, // Logical Minimum (0) 22
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0x25, 0x01, // Logical Maximum (1) 24
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0x75, 0x01, // Report Size (1) 26
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0x95, 0x05, // Report Count (5) 28 /* changed (was 5) */
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0x81, 0x02, // Input (Data,Var,Abs) 30
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0x05, 0x09, // Usage Page (Button) /* inserted */
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0x09, 0x4a, // Usage (0x4a) /* inserted to be translated as input usage 0x149: BTN_STYLUS3 */
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0x95, 0x01, // Report Count (1) /* inserted */
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0x81, 0x02, // Input (Data,Var,Abs) /* inserted */
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0x05, 0x0d, // Usage Page (Digitizers) /* inserted */
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0x09, 0x32, // Usage (In Range) 32
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0x75, 0x01, // Report Size (1) 34
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0x95, 0x01, // Report Count (1) 36
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0x81, 0x02, // Input (Data,Var,Abs) 38
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0x81, 0x03, // Input (Cnst,Var,Abs) 40
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0x05, 0x01, // Usage Page (Generic Desktop) 42
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0x09, 0x30, // Usage (X) 44
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0x09, 0x31, // Usage (Y) 46
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0x55, 0x0d, // Unit Exponent (-3) 48
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0x65, 0x33, // Unit (EnglishLinear: in³) 50
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 52
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0x35, 0x00, // Physical Minimum (0) 55
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0x46, 0x00, 0x08, // Physical Maximum (2048) 57
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0x75, 0x10, // Report Size (16) 60
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0x95, 0x02, // Report Count (2) 62
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0x81, 0x02, // Input (Data,Var,Abs) 64
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0x05, 0x0d, // Usage Page (Digitizers) 66
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0x09, 0x30, // Usage (Tip Pressure) 68
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0x26, 0xff, 0x3f, // Logical Maximum (16383) 70
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0x75, 0x10, // Report Size (16) 73
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0x95, 0x01, // Report Count (1) 75
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0x81, 0x02, // Input (Data,Var,Abs) 77
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0x09, 0x3d, // Usage (X Tilt) 79
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0x09, 0x3e, // Usage (Y Tilt) 81
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0x15, 0xa6, // Logical Minimum (-90) 83
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0x25, 0x5a, // Logical Maximum (90) 85
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0x75, 0x08, // Report Size (8) 87
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0x95, 0x02, // Report Count (2) 89
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0x81, 0x02, // Input (Data,Var,Abs) 91
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0xc0, // End Collection 93
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0xc0, // End Collection 94
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0x05, 0x0d, // Usage Page (Digitizers) 95
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0x09, 0x04, // Usage (Touch Screen) 97
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0xa1, 0x01, // Collection (Application) 99
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0x85, 0x04, // Report ID (4) 101
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0x09, 0x22, // Usage (Finger) 103
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0xa1, 0x02, // Collection (Logical) 105
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0x05, 0x0d, // Usage Page (Digitizers) 107
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0x95, 0x01, // Report Count (1) 109
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0x75, 0x06, // Report Size (6) 111
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0x09, 0x51, // Usage (Contact Id) 113
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0x15, 0x00, // Logical Minimum (0) 115
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0x25, 0x3f, // Logical Maximum (63) 117
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0x81, 0x02, // Input (Data,Var,Abs) 119
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0x09, 0x42, // Usage (Tip Switch) 121
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0x25, 0x01, // Logical Maximum (1) 123
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0x75, 0x01, // Report Size (1) 125
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0x95, 0x01, // Report Count (1) 127
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0x81, 0x02, // Input (Data,Var,Abs) 129
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0x75, 0x01, // Report Size (1) 131
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0x95, 0x01, // Report Count (1) 133
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0x81, 0x03, // Input (Cnst,Var,Abs) 135
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0x05, 0x01, // Usage Page (Generic Desktop) 137
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0x75, 0x10, // Report Size (16) 139
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0x55, 0x0e, // Unit Exponent (-2) 141
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0x65, 0x11, // Unit (SILinear: cm) 143
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0x09, 0x30, // Usage (X) 145
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 147
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0x35, 0x00, // Physical Minimum (0) 150
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0x46, 0x15, 0x0c, // Physical Maximum (3093) 152
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0x81, 0x42, // Input (Data,Var,Abs,Null) 155
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0x09, 0x31, // Usage (Y) 157
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 159
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0x46, 0xcb, 0x06, // Physical Maximum (1739) 162
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0x81, 0x42, // Input (Data,Var,Abs,Null) 165
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0x05, 0x0d, // Usage Page (Digitizers) 167
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0x09, 0x30, // Usage (Tip Pressure) 169
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0x26, 0xff, 0x1f, // Logical Maximum (8191) 171
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0x75, 0x10, // Report Size (16) 174
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0x95, 0x01, // Report Count (1) 176
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0x81, 0x02, // Input (Data,Var,Abs) 178
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0xc0, // End Collection 180
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0x05, 0x0d, // Usage Page (Digitizers) 181
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0x09, 0x22, // Usage (Finger) 183
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0xa1, 0x02, // Collection (Logical) 185
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0x05, 0x0d, // Usage Page (Digitizers) 187
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0x95, 0x01, // Report Count (1) 189
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0x75, 0x06, // Report Size (6) 191
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0x09, 0x51, // Usage (Contact Id) 193
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0x15, 0x00, // Logical Minimum (0) 195
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0x25, 0x3f, // Logical Maximum (63) 197
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0x81, 0x02, // Input (Data,Var,Abs) 199
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0x09, 0x42, // Usage (Tip Switch) 201
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0x25, 0x01, // Logical Maximum (1) 203
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0x75, 0x01, // Report Size (1) 205
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0x95, 0x01, // Report Count (1) 207
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0x81, 0x02, // Input (Data,Var,Abs) 209
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0x75, 0x01, // Report Size (1) 211
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0x95, 0x01, // Report Count (1) 213
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0x81, 0x03, // Input (Cnst,Var,Abs) 215
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0x05, 0x01, // Usage Page (Generic Desktop) 217
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0x75, 0x10, // Report Size (16) 219
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0x55, 0x0e, // Unit Exponent (-2) 221
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0x65, 0x11, // Unit (SILinear: cm) 223
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0x09, 0x30, // Usage (X) 225
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 227
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0x35, 0x00, // Physical Minimum (0) 230
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0x46, 0x15, 0x0c, // Physical Maximum (3093) 232
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0x81, 0x42, // Input (Data,Var,Abs,Null) 235
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0x09, 0x31, // Usage (Y) 237
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 239
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0x46, 0xcb, 0x06, // Physical Maximum (1739) 242
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0x81, 0x42, // Input (Data,Var,Abs,Null) 245
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0x05, 0x0d, // Usage Page (Digitizers) 247
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0x09, 0x30, // Usage (Tip Pressure) 249
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0x26, 0xff, 0x1f, // Logical Maximum (8191) 251
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0x75, 0x10, // Report Size (16) 254
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0x95, 0x01, // Report Count (1) 256
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0x81, 0x02, // Input (Data,Var,Abs) 258
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0xc0, // End Collection 260
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0x05, 0x0d, // Usage Page (Digitizers) 261
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0x09, 0x56, // Usage (Scan Time) 263
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0x55, 0x00, // Unit Exponent (0) 265
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0x65, 0x00, // Unit (None) 267
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0x27, 0xff, 0xff, 0xff, 0x7f, // Logical Maximum (2147483647) 269
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0x95, 0x01, // Report Count (1) 274
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0x75, 0x20, // Report Size (32) 276
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0x81, 0x02, // Input (Data,Var,Abs) 278
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0x09, 0x54, // Usage (Contact Count) 280
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0x25, 0x7f, // Logical Maximum (127) 282
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0x95, 0x01, // Report Count (1) 284
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0x75, 0x08, // Report Size (8) 286
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0x81, 0x02, // Input (Data,Var,Abs) 288
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0x75, 0x08, // Report Size (8) 290
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0x95, 0x08, // Report Count (8) 292
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0x81, 0x03, // Input (Cnst,Var,Abs) 294
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0x85, 0x05, // Report ID (5) 296
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0x09, 0x55, // Usage (Contact Max) 298
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0x25, 0x0a, // Logical Maximum (10) 300
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0x75, 0x08, // Report Size (8) 302
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0x95, 0x01, // Report Count (1) 304
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0xb1, 0x02, // Feature (Data,Var,Abs) 306
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0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 308
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0x09, 0xc5, // Usage (Vendor Usage 0xc5) 311
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0x85, 0x06, // Report ID (6) 313
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0x15, 0x00, // Logical Minimum (0) 315
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0x26, 0xff, 0x00, // Logical Maximum (255) 317
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0x75, 0x08, // Report Size (8) 320
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0x96, 0x00, 0x01, // Report Count (256) 322
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0xb1, 0x02, // Feature (Data,Var,Abs) 325
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0xc0, // End Collection 327
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};
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SEC(HID_BPF_RDESC_FIXUP)
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int BPF_PROG(hid_fix_rdesc_huion_kamvas_pro_19, struct hid_bpf_ctx *hctx)
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{
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__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */);
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if (!data)
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return 0; /* EPERM check */
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__builtin_memcpy(data, fixed_rdesc, sizeof(fixed_rdesc));
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return sizeof(fixed_rdesc);
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}
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/*
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* This tablet reports the 3rd button through invert, but this conflict
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* with the normal eraser mode.
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* Fortunately, before entering eraser mode, (so Invert = 1),
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* the tablet always sends an out-of-proximity event.
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* So we can detect that single event and:
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* - if there was none but the invert bit was toggled: this is the
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* third button
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* - if there was this out-of-proximity event, we are entering
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* eraser mode, and we will until the next out-of-proximity.
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*/
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SEC(HID_BPF_DEVICE_EVENT)
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int BPF_PROG(kamvas_pro_19_fix_3rd_button, struct hid_bpf_ctx *hctx)
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{
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__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */);
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if (!data)
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return 0; /* EPERM check */
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if (data[0] != 0x0a) /* not the pen report ID */
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return 0;
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/* stylus is out of range */
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if (!(data[1] & 0x40)) {
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prev_was_out_of_range = true;
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in_eraser_mode = false;
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return 0;
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}
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/* going into eraser mode (Invert = 1) only happens after an
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* out of range event
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*/
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if (prev_was_out_of_range && (data[1] & 0x18))
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in_eraser_mode = true;
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/* eraser mode works fine */
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if (in_eraser_mode)
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return 0;
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/* copy the Invert bit reported for the 3rd button in bit 7 */
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if (data[1] & 0x08)
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data[1] |= 0x20;
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/* clear Invert bit now that it was copied */
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data[1] &= 0xf7;
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prev_was_out_of_range = false;
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return 0;
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}
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HID_BPF_OPS(huion_Kamvas_pro_19) = {
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.hid_rdesc_fixup = (void *)hid_fix_rdesc_huion_kamvas_pro_19,
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.hid_device_event = (void *)kamvas_pro_19_fix_3rd_button,
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};
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SEC("syscall")
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int probe(struct hid_bpf_probe_args *ctx)
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{
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ctx->retval = ctx->rdesc_size != 328;
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if (ctx->retval)
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ctx->retval = -EINVAL;
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/* ensure the kernel isn't fixed already */
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if (ctx->rdesc[17] != 0x43) /* Secondary Tip Switch */
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ctx->retval = -EINVAL;
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struct hid_bpf_ctx *hctx = hid_bpf_allocate_context(ctx->hid);
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if (!hctx) {
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return ctx->retval = -EINVAL;
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return 0;
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}
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const char *name = hctx->hid->name;
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/* strip out TEST_PREFIX */
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if (!__builtin_memcmp(name, TEST_PREFIX, sizeof(TEST_PREFIX) - 1))
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name += sizeof(TEST_PREFIX) - 1;
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if (__builtin_memcmp(name, NAME_KAMVAS_PRO_19, sizeof(NAME_KAMVAS_PRO_19)))
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ctx->retval = -EINVAL;
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hid_bpf_release_context(hctx);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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