diff mbox series

[v2,1/3] HID: bpf: Fix NKRO on Mistel MD770

Message ID 20241017-import_bpf_6-13-v2-1-6a7acb89a97f@kernel.org (mailing list archive)
State New
Delegated to: Jiri Kosina
Headers show
Series HID: bpf: add a couple of HID-BPF device fixes | expand

Commit Message

Benjamin Tissoires Oct. 17, 2024, 4:34 p.m. UTC 
Mistel MD770 keyboard (using Holtek Semiconductor, Inc. controller) has
a quirk in report descriptor in one of its interfaces (more detail in
the source file). Fix up the descriptor to allow NKRO to work again.

Tested by loading the BPF program and confirming that 8 simultaneous
keypresses work.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=218495
Link: https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/122
Signed-off-by: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

---

no changes in v2
---
 drivers/hid/bpf/progs/Mistel__MD770.bpf.c | 154 ++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
diff mbox series

Patch

diff --git a/drivers/hid/bpf/progs/Mistel__MD770.bpf.c b/drivers/hid/bpf/progs/Mistel__MD770.bpf.c
new file mode 100644
index 0000000000000000000000000000000000000000..fb8b5a6968b125ed88a456aefb427ede0e0bfa9b
--- /dev/null
+++ b/drivers/hid/bpf/progs/Mistel__MD770.bpf.c
@@ -0,0 +1,154 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Tatsuyuki Ishi
+ */
+
+#include "vmlinux.h"
+#include "hid_bpf.h"
+#include "hid_bpf_helpers.h"
+#include <bpf/bpf_tracing.h>
+
+#define VID_HOLTEK	0x04D9
+#define PID_MD770	0x0339
+#define RDESC_SIZE	203
+
+HID_BPF_CONFIG(
+	HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_HOLTEK, PID_MD770)
+);
+
+/*
+ * The Mistel MD770 keyboard reports the first 6 simultaneous key presses
+ * through the first interface, and anything beyond that through a second
+ * interface. Unfortunately, the second interface's report descriptor has an
+ * error, causing events to be malformed and ignored. This HID-BPF driver
+ * fixes the descriptor to allow NKRO to work again.
+ *
+ * For reference, this is the original report descriptor:
+ *
+ * 0x05, 0x01,        // Usage Page (Generic Desktop)        0
+ * 0x09, 0x80,        // Usage (System Control)              2
+ * 0xa1, 0x01,        // Collection (Application)            4
+ * 0x85, 0x01,        //  Report ID (1)                      6
+ * 0x19, 0x81,        //  Usage Minimum (129)                8
+ * 0x29, 0x83,        //  Usage Maximum (131)                10
+ * 0x15, 0x00,        //  Logical Minimum (0)                12
+ * 0x25, 0x01,        //  Logical Maximum (1)                14
+ * 0x95, 0x03,        //  Report Count (3)                   16
+ * 0x75, 0x01,        //  Report Size (1)                    18
+ * 0x81, 0x02,        //  Input (Data,Var,Abs)               20
+ * 0x95, 0x01,        //  Report Count (1)                   22
+ * 0x75, 0x05,        //  Report Size (5)                    24
+ * 0x81, 0x01,        //  Input (Cnst,Arr,Abs)               26
+ * 0xc0,              // End Collection                      28
+ * 0x05, 0x0c,        // Usage Page (Consumer Devices)       29
+ * 0x09, 0x01,        // Usage (Consumer Control)            31
+ * 0xa1, 0x01,        // Collection (Application)            33
+ * 0x85, 0x02,        //  Report ID (2)                      35
+ * 0x15, 0x00,        //  Logical Minimum (0)                37
+ * 0x25, 0x01,        //  Logical Maximum (1)                39
+ * 0x95, 0x12,        //  Report Count (18)                  41
+ * 0x75, 0x01,        //  Report Size (1)                    43
+ * 0x0a, 0x83, 0x01,  //  Usage (AL Consumer Control Config) 45
+ * 0x0a, 0x8a, 0x01,  //  Usage (AL Email Reader)            48
+ * 0x0a, 0x92, 0x01,  //  Usage (AL Calculator)              51
+ * 0x0a, 0x94, 0x01,  //  Usage (AL Local Machine Browser)   54
+ * 0x09, 0xcd,        //  Usage (Play/Pause)                 57
+ * 0x09, 0xb7,        //  Usage (Stop)                       59
+ * 0x09, 0xb6,        //  Usage (Scan Previous Track)        61
+ * 0x09, 0xb5,        //  Usage (Scan Next Track)            63
+ * 0x09, 0xe2,        //  Usage (Mute)                       65
+ * 0x09, 0xea,        //  Usage (Volume Down)                67
+ * 0x09, 0xe9,        //  Usage (Volume Up)                  69
+ * 0x0a, 0x21, 0x02,  //  Usage (AC Search)                  71
+ * 0x0a, 0x23, 0x02,  //  Usage (AC Home)                    74
+ * 0x0a, 0x24, 0x02,  //  Usage (AC Back)                    77
+ * 0x0a, 0x25, 0x02,  //  Usage (AC Forward)                 80
+ * 0x0a, 0x26, 0x02,  //  Usage (AC Stop)                    83
+ * 0x0a, 0x27, 0x02,  //  Usage (AC Refresh)                 86
+ * 0x0a, 0x2a, 0x02,  //  Usage (AC Bookmarks)               89
+ * 0x81, 0x02,        //  Input (Data,Var,Abs)               92
+ * 0x95, 0x01,        //  Report Count (1)                   94
+ * 0x75, 0x0e,        //  Report Size (14)                   96
+ * 0x81, 0x01,        //  Input (Cnst,Arr,Abs)               98
+ * 0xc0,              // End Collection                      100
+ * 0x05, 0x01,        // Usage Page (Generic Desktop)        101
+ * 0x09, 0x02,        // Usage (Mouse)                       103
+ * 0xa1, 0x01,        // Collection (Application)            105
+ * 0x09, 0x01,        //  Usage (Pointer)                    107
+ * 0xa1, 0x00,        //  Collection (Physical)              109
+ * 0x85, 0x03,        //   Report ID (3)                     111
+ * 0x05, 0x09,        //   Usage Page (Button)               113
+ * 0x19, 0x01,        //   Usage Minimum (1)                 115
+ * 0x29, 0x08,        //   Usage Maximum (8)                 117
+ * 0x15, 0x00,        //   Logical Minimum (0)               119
+ * 0x25, 0x01,        //   Logical Maximum (1)               121
+ * 0x75, 0x01,        //   Report Size (1)                   123
+ * 0x95, 0x08,        //   Report Count (8)                  125
+ * 0x81, 0x02,        //   Input (Data,Var,Abs)              127
+ * 0x05, 0x01,        //   Usage Page (Generic Desktop)      129
+ * 0x09, 0x30,        //   Usage (X)                         131
+ * 0x09, 0x31,        //   Usage (Y)                         133
+ * 0x16, 0x01, 0x80,  //   Logical Minimum (-32767)          135
+ * 0x26, 0xff, 0x7f,  //   Logical Maximum (32767)           138
+ * 0x75, 0x10,        //   Report Size (16)                  141
+ * 0x95, 0x02,        //   Report Count (2)                  143
+ * 0x81, 0x06,        //   Input (Data,Var,Rel)              145
+ * 0x09, 0x38,        //   Usage (Wheel)                     147
+ * 0x15, 0x81,        //   Logical Minimum (-127)            149
+ * 0x25, 0x7f,        //   Logical Maximum (127)             151
+ * 0x75, 0x08,        //   Report Size (8)                   153
+ * 0x95, 0x01,        //   Report Count (1)                  155
+ * 0x81, 0x06,        //   Input (Data,Var,Rel)              157
+ * 0x05, 0x0c,        //   Usage Page (Consumer Devices)     159
+ * 0x0a, 0x38, 0x02,  //   Usage (AC Pan)                    161
+ * 0x95, 0x01,        //   Report Count (1)                  164
+ * 0x81, 0x06,        //   Input (Data,Var,Rel)              166
+ * 0xc0,              //  End Collection                     168
+ * 0xc0,              // End Collection                      169
+ * 0x05, 0x01,        // Usage Page (Generic Desktop)        170
+ * 0x09, 0x06,        // Usage (Keyboard)                    172
+ * 0xa1, 0x01,        // Collection (Application)            174
+ * 0x85, 0x04,        //  Report ID (4)                      176
+ * 0x05, 0x07,        //  Usage Page (Keyboard)              178
+ * 0x95, 0x01,        //  Report Count (1)                   180
+ * 0x75, 0x08,        //  Report Size (8)                    182
+ * 0x81, 0x03,        //  Input (Cnst,Var,Abs)               184
+ * 0x95, 0xe8,        //  Report Count (232)                 186
+ * 0x75, 0x01,        //  Report Size (1)                    188
+ * 0x15, 0x00,        //  Logical Minimum (0)                190
+ * 0x25, 0x01,        //  Logical Maximum (1)                192
+ * 0x05, 0x07,        //  Usage Page (Keyboard)              194
+ * 0x19, 0x00,        //  Usage Minimum (0)                  196
+ * 0x29, 0xe7,        //  Usage Maximum (231)                198
+ * 0x81, 0x00,        //  Input (Data,Arr,Abs)               200  <- change to 0x81, 0x02 (Data,Var,Abs)
+ * 0xc0,              // End Collection                      202
+ */
+
+SEC(HID_BPF_RDESC_FIXUP)
+int BPF_PROG(hid_rdesc_fixup_mistel_md770, struct hid_bpf_ctx *hctx)
+{
+	__u8 *data = hid_bpf_get_data(hctx, 0, HID_MAX_DESCRIPTOR_SIZE);
+
+	if (!data)
+		return 0; /* EPERM check */
+
+	if (data[201] == 0x00)
+		data[201] = 0x02;
+
+	return 0;
+}
+
+HID_BPF_OPS(mistel_md770) = {
+	.hid_rdesc_fixup = (void *)hid_rdesc_fixup_mistel_md770,
+};
+
+SEC("syscall")
+int probe(struct hid_bpf_probe_args *ctx)
+{
+	ctx->retval = ctx->rdesc_size != RDESC_SIZE;
+	if (ctx->retval)
+		ctx->retval = -EINVAL;
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";