This tablets gets a lot of things wrong: - the secondary button is reported through Secondary Tip Switch - the third button is reported through Invert
Fortunately, before entering eraser mode, (so Invert = 1), the tablet always sends an out-of-proximity event. So we can detect that single event and: - if there was none but the invert bit was toggled: this is the third button - if there was this out-of-proximity event, we are entering eraser mode, and we will until the next out-of-proximity.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c | 290 +++++++++++++++++++++++ 1 file changed, 290 insertions(+)
diff --git a/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c new file mode 100644 index 000000000000..ff759f2276f9 --- /dev/null +++ b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2024 Benjamin Tissoires + */ + +#include "vmlinux.h" +#include "hid_bpf.h" +#include "hid_bpf_helpers.h" +#include <bpf/bpf_tracing.h> + +#define VID_HUION 0x256C +#define PID_KAMVAS_PRO_19 0x006B +#define NAME_KAMVAS_PRO_19 "HUION Huion Tablet_GT1902" + +#define TEST_PREFIX "uhid test " + +HID_BPF_CONFIG( + HID_DEVICE(BUS_USB, HID_GROUP_MULTITOUCH_WIN_8, VID_HUION, PID_KAMVAS_PRO_19), +); + +bool prev_was_out_of_range; +bool in_eraser_mode; + +/* + * We need to amend the report descriptor for the following: + * - the second button is reported through Secondary Tip Switch instead of Secondary Barrel Switch + * - the third button is reported through Invert, and we need some room to report it. + * + */ +static const __u8 fixed_rdesc[] = { + 0x05, 0x0d, // Usage Page (Digitizers) 0 + 0x09, 0x02, // Usage (Pen) 2 + 0xa1, 0x01, // Collection (Application) 4 + 0x85, 0x0a, // Report ID (10) 6 + 0x09, 0x20, // Usage (Stylus) 8 + 0xa1, 0x01, // Collection (Application) 10 + 0x09, 0x42, // Usage (Tip Switch) 12 + 0x09, 0x44, // Usage (Barrel Switch) 14 + 0x09, 0x5a, // Usage (Secondary Barrel Switch) 16 /* changed from Secondary Tip Switch */ + 0x09, 0x3c, // Usage (Invert) 18 + 0x09, 0x45, // Usage (Eraser) 20 + 0x15, 0x00, // Logical Minimum (0) 22 + 0x25, 0x01, // Logical Maximum (1) 24 + 0x75, 0x01, // Report Size (1) 26 + 0x95, 0x05, // Report Count (5) 28 /* changed (was 5) */ + 0x81, 0x02, // Input (Data,Var,Abs) 30 + 0x05, 0x09, // Usage Page (Button) /* inserted */ + 0x09, 0x4a, // Usage (0x4a) /* inserted to be translated as input usage 0x149: BTN_STYLUS3 */ + 0x95, 0x01, // Report Count (1) /* inserted */ + 0x81, 0x02, // Input (Data,Var,Abs) /* inserted */ + 0x05, 0x0d, // Usage Page (Digitizers) /* inserted */ + 0x09, 0x32, // Usage (In Range) 32 + 0x75, 0x01, // Report Size (1) 34 + 0x95, 0x01, // Report Count (1) 36 + 0x81, 0x02, // Input (Data,Var,Abs) 38 + 0x81, 0x03, // Input (Cnst,Var,Abs) 40 + 0x05, 0x01, // Usage Page (Generic Desktop) 42 + 0x09, 0x30, // Usage (X) 44 + 0x09, 0x31, // Usage (Y) 46 + 0x55, 0x0d, // Unit Exponent (-3) 48 + 0x65, 0x33, // Unit (EnglishLinear: in³) 50 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 52 + 0x35, 0x00, // Physical Minimum (0) 55 + 0x46, 0x00, 0x08, // Physical Maximum (2048) 57 + 0x75, 0x10, // Report Size (16) 60 + 0x95, 0x02, // Report Count (2) 62 + 0x81, 0x02, // Input (Data,Var,Abs) 64 + 0x05, 0x0d, // Usage Page (Digitizers) 66 + 0x09, 0x30, // Usage (Tip Pressure) 68 + 0x26, 0xff, 0x3f, // Logical Maximum (16383) 70 + 0x75, 0x10, // Report Size (16) 73 + 0x95, 0x01, // Report Count (1) 75 + 0x81, 0x02, // Input (Data,Var,Abs) 77 + 0x09, 0x3d, // Usage (X Tilt) 79 + 0x09, 0x3e, // Usage (Y Tilt) 81 + 0x15, 0xa6, // Logical Minimum (-90) 83 + 0x25, 0x5a, // Logical Maximum (90) 85 + 0x75, 0x08, // Report Size (8) 87 + 0x95, 0x02, // Report Count (2) 89 + 0x81, 0x02, // Input (Data,Var,Abs) 91 + 0xc0, // End Collection 93 + 0xc0, // End Collection 94 + 0x05, 0x0d, // Usage Page (Digitizers) 95 + 0x09, 0x04, // Usage (Touch Screen) 97 + 0xa1, 0x01, // Collection (Application) 99 + 0x85, 0x04, // Report ID (4) 101 + 0x09, 0x22, // Usage (Finger) 103 + 0xa1, 0x02, // Collection (Logical) 105 + 0x05, 0x0d, // Usage Page (Digitizers) 107 + 0x95, 0x01, // Report Count (1) 109 + 0x75, 0x06, // Report Size (6) 111 + 0x09, 0x51, // Usage (Contact Id) 113 + 0x15, 0x00, // Logical Minimum (0) 115 + 0x25, 0x3f, // Logical Maximum (63) 117 + 0x81, 0x02, // Input (Data,Var,Abs) 119 + 0x09, 0x42, // Usage (Tip Switch) 121 + 0x25, 0x01, // Logical Maximum (1) 123 + 0x75, 0x01, // Report Size (1) 125 + 0x95, 0x01, // Report Count (1) 127 + 0x81, 0x02, // Input (Data,Var,Abs) 129 + 0x75, 0x01, // Report Size (1) 131 + 0x95, 0x01, // Report Count (1) 133 + 0x81, 0x03, // Input (Cnst,Var,Abs) 135 + 0x05, 0x01, // Usage Page (Generic Desktop) 137 + 0x75, 0x10, // Report Size (16) 139 + 0x55, 0x0e, // Unit Exponent (-2) 141 + 0x65, 0x11, // Unit (SILinear: cm) 143 + 0x09, 0x30, // Usage (X) 145 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 147 + 0x35, 0x00, // Physical Minimum (0) 150 + 0x46, 0x15, 0x0c, // Physical Maximum (3093) 152 + 0x81, 0x42, // Input (Data,Var,Abs,Null) 155 + 0x09, 0x31, // Usage (Y) 157 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 159 + 0x46, 0xcb, 0x06, // Physical Maximum (1739) 162 + 0x81, 0x42, // Input (Data,Var,Abs,Null) 165 + 0x05, 0x0d, // Usage Page (Digitizers) 167 + 0x09, 0x30, // Usage (Tip Pressure) 169 + 0x26, 0xff, 0x1f, // Logical Maximum (8191) 171 + 0x75, 0x10, // Report Size (16) 174 + 0x95, 0x01, // Report Count (1) 176 + 0x81, 0x02, // Input (Data,Var,Abs) 178 + 0xc0, // End Collection 180 + 0x05, 0x0d, // Usage Page (Digitizers) 181 + 0x09, 0x22, // Usage (Finger) 183 + 0xa1, 0x02, // Collection (Logical) 185 + 0x05, 0x0d, // Usage Page (Digitizers) 187 + 0x95, 0x01, // Report Count (1) 189 + 0x75, 0x06, // Report Size (6) 191 + 0x09, 0x51, // Usage (Contact Id) 193 + 0x15, 0x00, // Logical Minimum (0) 195 + 0x25, 0x3f, // Logical Maximum (63) 197 + 0x81, 0x02, // Input (Data,Var,Abs) 199 + 0x09, 0x42, // Usage (Tip Switch) 201 + 0x25, 0x01, // Logical Maximum (1) 203 + 0x75, 0x01, // Report Size (1) 205 + 0x95, 0x01, // Report Count (1) 207 + 0x81, 0x02, // Input (Data,Var,Abs) 209 + 0x75, 0x01, // Report Size (1) 211 + 0x95, 0x01, // Report Count (1) 213 + 0x81, 0x03, // Input (Cnst,Var,Abs) 215 + 0x05, 0x01, // Usage Page (Generic Desktop) 217 + 0x75, 0x10, // Report Size (16) 219 + 0x55, 0x0e, // Unit Exponent (-2) 221 + 0x65, 0x11, // Unit (SILinear: cm) 223 + 0x09, 0x30, // Usage (X) 225 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 227 + 0x35, 0x00, // Physical Minimum (0) 230 + 0x46, 0x15, 0x0c, // Physical Maximum (3093) 232 + 0x81, 0x42, // Input (Data,Var,Abs,Null) 235 + 0x09, 0x31, // Usage (Y) 237 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 239 + 0x46, 0xcb, 0x06, // Physical Maximum (1739) 242 + 0x81, 0x42, // Input (Data,Var,Abs,Null) 245 + 0x05, 0x0d, // Usage Page (Digitizers) 247 + 0x09, 0x30, // Usage (Tip Pressure) 249 + 0x26, 0xff, 0x1f, // Logical Maximum (8191) 251 + 0x75, 0x10, // Report Size (16) 254 + 0x95, 0x01, // Report Count (1) 256 + 0x81, 0x02, // Input (Data,Var,Abs) 258 + 0xc0, // End Collection 260 + 0x05, 0x0d, // Usage Page (Digitizers) 261 + 0x09, 0x56, // Usage (Scan Time) 263 + 0x55, 0x00, // Unit Exponent (0) 265 + 0x65, 0x00, // Unit (None) 267 + 0x27, 0xff, 0xff, 0xff, 0x7f, // Logical Maximum (2147483647) 269 + 0x95, 0x01, // Report Count (1) 274 + 0x75, 0x20, // Report Size (32) 276 + 0x81, 0x02, // Input (Data,Var,Abs) 278 + 0x09, 0x54, // Usage (Contact Count) 280 + 0x25, 0x7f, // Logical Maximum (127) 282 + 0x95, 0x01, // Report Count (1) 284 + 0x75, 0x08, // Report Size (8) 286 + 0x81, 0x02, // Input (Data,Var,Abs) 288 + 0x75, 0x08, // Report Size (8) 290 + 0x95, 0x08, // Report Count (8) 292 + 0x81, 0x03, // Input (Cnst,Var,Abs) 294 + 0x85, 0x05, // Report ID (5) 296 + 0x09, 0x55, // Usage (Contact Max) 298 + 0x25, 0x0a, // Logical Maximum (10) 300 + 0x75, 0x08, // Report Size (8) 302 + 0x95, 0x01, // Report Count (1) 304 + 0xb1, 0x02, // Feature (Data,Var,Abs) 306 + 0x06, 0x00, 0xff, // Usage Page (Vendor Defined Page 1) 308 + 0x09, 0xc5, // Usage (Vendor Usage 0xc5) 311 + 0x85, 0x06, // Report ID (6) 313 + 0x15, 0x00, // Logical Minimum (0) 315 + 0x26, 0xff, 0x00, // Logical Maximum (255) 317 + 0x75, 0x08, // Report Size (8) 320 + 0x96, 0x00, 0x01, // Report Count (256) 322 + 0xb1, 0x02, // Feature (Data,Var,Abs) 325 + 0xc0, // End Collection 327 +}; + +SEC("fmod_ret/hid_bpf_rdesc_fixup") +int BPF_PROG(hid_fix_rdesc_huion_kamvas_pro_19, struct hid_bpf_ctx *hctx) +{ + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */); + + if (!data) + return 0; /* EPERM check */ + + __builtin_memcpy(data, fixed_rdesc, sizeof(fixed_rdesc)); + + return sizeof(fixed_rdesc); +} + +/* + * This tablet reports the 3rd button through invert, but this conflict + * with the normal eraser mode. + * Fortunately, before entering eraser mode, (so Invert = 1), + * the tablet always sends an out-of-proximity event. + * So we can detect that single event and: + * - if there was none but the invert bit was toggled: this is the + * third button + * - if there was this out-of-proximity event, we are entering + * eraser mode, and we will until the next out-of-proximity. + */ +SEC("fmod_ret/hid_bpf_device_event") +int BPF_PROG(kamvas_pro_19_fix_3rd_button, struct hid_bpf_ctx *hctx) +{ + __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); + + if (!data) + return 0; /* EPERM check */ + + if (data[0] != 0x0a) /* not the pen report ID */ + return 0; + + /* stylus is out of range */ + if (!(data[1] & 0x40)) { + prev_was_out_of_range = true; + in_eraser_mode = false; + return 0; + } + + /* going into eraser mode (Invert = 1) only happens after an + * out of range event + */ + if (prev_was_out_of_range && (data[1] & 0x18)) + in_eraser_mode = true; + + /* eraser mode works fine */ + if (in_eraser_mode) + return 0; + + /* copy the Invert bit reported for the 3rd button in bit 7 */ + if (data[1] & 0x08) + data[1] |= 0x20; + + /* clear Invert bit now that it was copied */ + data[1] &= 0xf7; + + prev_was_out_of_range = false; + + return 0; +} + +SEC("syscall") +int probe(struct hid_bpf_probe_args *ctx) +{ + ctx->retval = ctx->rdesc_size != 328; + if (ctx->retval) + ctx->retval = -EINVAL; + + /* ensure the kernel isn't fixed already */ + if (ctx->rdesc[17] != 0x43) /* Secondary Tip Switch */ + ctx->retval = -EINVAL; + + struct hid_bpf_ctx *hctx = hid_bpf_allocate_context(ctx->hid); + + if (!hctx) { + return ctx->retval = -EINVAL; + return 0; + } + + const char *name = hctx->hid->name; + + /* strip out TEST_PREFIX */ + if (!__builtin_memcmp(name, TEST_PREFIX, sizeof(TEST_PREFIX) - 1)) + name += sizeof(TEST_PREFIX) - 1; + + if (__builtin_memcmp(name, NAME_KAMVAS_PRO_19, sizeof(NAME_KAMVAS_PRO_19))) + ctx->retval = -EINVAL; + + hid_bpf_release_context(hctx); + + return 0; +} + +char _license[] SEC("license") = "GPL";