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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2023 Benjamin Tissoires
*/
#include "vmlinux.h"
#include "hid_bpf.h"
#include "hid_bpf_helpers.h"
#include <bpf/bpf_tracing.h>
#define VID_HP 0x03F0
#define PID_ELITE_PRESENTER 0x464A
HID_BPF_CONFIG(
HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_GENERIC, VID_HP, PID_ELITE_PRESENTER)
);
/*
* Already fixed as of commit 0db117359e47 ("HID: add quirk for 03f0:464a
* HP Elite Presenter Mouse") in the kernel, but this is a slightly better
* fix.
*
* The HP Elite Presenter Mouse HID Record Descriptor shows
* two mice (Report ID 0x1 and 0x2), one keypad (Report ID 0x5),
* two Consumer Controls (Report IDs 0x6 and 0x3).
* Prior to these fixes it registers one mouse, one keypad
* and one Consumer Control, and it was usable only as a
* digital laser pointer (one of the two mouses).
* We replace the second mouse collection with a pointer collection,
* allowing to use the device both as a mouse and a digital laser
* pointer.
*/
SEC(HID_BPF_RDESC_FIXUP)
int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx)
{
__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
if (!data)
return 0; /* EPERM check */
/* replace application mouse by application pointer on the second collection */
if (data[79] == 0x02)
data[79] = 0x01;
return 0;
}
HID_BPF_OPS(hp_elite_presenter) = {
.hid_rdesc_fixup = (void *)hid_fix_rdesc,
};
SEC("syscall")
int probe(struct hid_bpf_probe_args *ctx)
{
ctx->retval = ctx->rdesc_size != 264;
if (ctx->retval)
ctx->retval = -EINVAL;
return 0;
}
char _license[] SEC("license") = "GPL";
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