From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 420B849EC5D; Mon, 31 Aug 2026 13:40:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183653; cv=none; b=kixJB+7hl7l7v4Pkia1UXqlhQUE0whNF6a0cCGY+p9D9XCeqsh8j17pdbTiH9x6S1Rb5P5O8T/HknQ0aMXMt6uxLRQMYTusJQKOSjHiOHUnZBIRy4G+6Rl+F3s6fXiRiAFQ2kLdn3b0NB+dd0GLiT1DCyRQS9smgd/JE/nPd+LI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183653; c=relaxed/simple; bh=6GQHGreEhaSHdft71s4xhZbDHO+bTnsSAFAa0HeMws4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UctGhGB7chcqkeWYcG3Ar2GsPx5ISYyhuizB1/nWRFWh6z/e4seZHQ8ZNrSeMJVlS76m/FXWeRky2wFhdZjaiaulRjSogqF0tq6kpGfFDyBQbNt3uZt39Cr+9f+f8blXbhHecWcxe7TrVXIkuvXSqRtchNMPkJwmG1VDQS6ZNDQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QP0ilfwA; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QP0ilfwA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E3761F000E9; Mon, 31 Aug 2026 13:40:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788183652; bh=4MKAJSJrngSB4caqVUmq/Ucm+1QQofYy+/cLNrFbWyw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QP0ilfwAdj2Yvj05WzG0AsM7P+L6ZwyD+7iAyGaADmP0RG9oOGl7lCIv+L6dx1MId Bsek9oAkfdRAwiJal/ef6HoBPjCrAooxRoloaCTHngNZdHIv/RlA5WfbUa9E6eU/Dl msiS8zUxbMfFc6gxKYHNgtCdZkIFFrhly6ewLHEBPwRCfvzY2JIs8unUK+R36JRNOv RRBP2IYq6u32Cxs0/Hwb/cmOwuN3Ohfo29s6R3YaCg5/qxQvXiM5ptN3lILvQducYL gYi44m7RYLx9N4W9XvZqBl33Gm1t56xlGz2BEZSQqHU0lXohgRTD0Hub8aBDQkbOd4 fXE1BTC7hcxQA== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Nikhil Chatterjee , Benjamin Tissoires , Sasha Levin , jikos@kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org Subject: [PATCH AUTOSEL 6.18-6.1] HID: bpf: Add Huion Inspiroy Frego M button quirk Date: Mon, 31 Aug 2026 09:24:10 -0400 Message-ID: <20260831133314.4125787-222-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831133314.4125787-1-sashal@kernel.org> References: <20260831133314.4125787-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.48 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Nikhil Chatterjee [ Upstream commit 857e71cb0a538b1660743a4267a1e789575f7966 ] The Huion Inspiroy Frego M pen report descriptor exposes the second side button as Secondary Tip Switch instead of Secondary Barrel Switch. This makes userspace see the control as the wrong pen button. Add a HID-BPF report descriptor fixup for the Bluetooth 256c:8251 device and USB 256c:2012 L610 variant. The fixup matches the expected pen descriptor and rewrites the offending usage from Secondary Tip Switch to Secondary Barrel Switch. Tested by building the HID-BPF object with: make -C drivers/hid/bpf/progs Huion__Inspiroy-Frego-M.bpf.o Signed-off-by: Nikhil Chatterjee Signed-off-by: Benjamin Tissoires Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: The background git searches finished and match the earlier analysis: - **`git log --grep="Frego"` / `--grep="Inspiroy Frego"`** — no matches in this tree; the quirk is not present in 6.18.44. - **`git log --grep="8251"` under `drivers/hid/`** — only an unrelated HID debugging commit, not this device. That confirms the patch would be a new addition here, consistent with the **YES** backport recommendation. .../bpf/progs/Huion__Inspiroy-Frego-M.bpf.c | 87 +++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 drivers/hid/bpf/progs/Huion__Inspiroy-Frego-M.bpf.c diff --git a/drivers/hid/bpf/progs/Huion__Inspiroy-Frego-M.bpf.c b/drivers/hid/bpf/progs/Huion__Inspiroy-Frego-M.bpf.c new file mode 100644 index 0000000000000..e6ba2295dc775 --- /dev/null +++ b/drivers/hid/bpf/progs/Huion__Inspiroy-Frego-M.bpf.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include "vmlinux.h" +#include "hid_bpf.h" +#include "hid_bpf_helpers.h" +#include + +/* + * Huion Inspiroy Frego M Pen Tablet + * Model L610 + * 256c:8251 (Bluetooth) + * 256c:2012 (USB) + */ +#define VID_HUION 0x256C +#define PID_INSPIROY_FREGO_M 0x8251 +#define PID_L610 0x2012 + +#define PEN_RDESC_SIZE 125 +#define SECONDARY_SWITCH_OFFSET 17 + +HID_BPF_CONFIG( + HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_GENERIC, VID_HUION, PID_INSPIROY_FREGO_M), + HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_HUION, PID_L610) +); + +/* + * The pen descriptor reports the second side button as Secondary Tip Switch + * instead of Secondary Barrel Switch. + * + * Relevant part of the original pen report descriptor: + * + * 0x09, 0x42, // Usage (Tip Switch) 12 + * 0x09, 0x44, // Usage (Barrel Switch) 14 + * 0x09, 0x43, // Usage (Secondary Tip Switch) 16 <- change to 0x5a + * 0x09, 0x3c, // Usage (Invert) 18 + * 0x09, 0x45, // Usage (Eraser) 20 + * 0x15, 0x00, // Logical Minimum (0) 22 + * 0x25, 0x01, // Logical Maximum (1) 24 + */ +SEC(HID_BPF_RDESC_FIXUP) +int BPF_PROG(fix_secondary_barrel_rdesc, 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 */ + + if (hctx->size != PEN_RDESC_SIZE) + return 0; + + if (data[0] != 0x05 || data[1] != 0x0d || /* Usage Page (Digitizers) */ + data[2] != 0x09 || data[3] != 0x02 || /* Usage (Pen) */ + data[16] != 0x09 || + data[SECONDARY_SWITCH_OFFSET] != 0x43) /* Secondary Tip Switch */ + return 0; + + data[SECONDARY_SWITCH_OFFSET] = 0x5a; + + return 0; +} + +HID_BPF_OPS(fix_secondary_barrel) = { + .hid_rdesc_fixup = (void *)fix_secondary_barrel_rdesc, +}; + +SEC("syscall") +int probe(struct hid_bpf_probe_args *ctx) +{ + ctx->retval = ctx->rdesc_size != PEN_RDESC_SIZE; + if (ctx->retval) { + ctx->retval = -EINVAL; + return 0; + } + + if (ctx->rdesc[0] != 0x05 || ctx->rdesc[1] != 0x0d || /* Usage Page (Digitizers) */ + ctx->rdesc[2] != 0x09 || ctx->rdesc[3] != 0x02 || /* Usage (Pen) */ + ctx->rdesc[16] != 0x09 || + ctx->rdesc[SECONDARY_SWITCH_OFFSET] != 0x43) { /* Secondary Tip Switch */ + ctx->retval = -EINVAL; + return 0; + } + + ctx->retval = 0; + + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.53.0