From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.42 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794380228; b=FIJTl0lvWIWj19IA2AByUlso3EsyywA1Ik4TEBxiAHTiSsrnJZZNzLSEs4SA2mlm+Rjj rnwOjEQolZOlMOhK+iH2zWzY8lqKmTn9qAiwlAYi4oY5pDgGxLqeJOFSkIu0387nq9bg3 l8XAhpK/0Wk3gqwOCR5jpUTNyPi7lFcTk5l306NDFKFn7xVfS93o0bzJLNTsaotBCJbjV GRbJ2Sra+AgQMd8UTQRkKalbgxFTwJcIzVE035A4YBula2ekCb2vNACbwfMFMcIhoexg/ z2l98RgJjCPDGGH5HQLm0qSWmKGeUNhQAhGGqVY9ur5bIKPUhrl561w3C5qsUfptssg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794380228; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:Date:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding: Message-Id:References:In-Reply-To:To:Cc:X-Mailer; bh=lZaigarthkYfk+LJ/id0he7EntFXTEZZC4zUNeoO63c=; b=AbLcfNhDdkjm5+/Ots9Me2BRtm52IVvf8zQbR6q2w/KEGuThA9pHV2mo7mGaL/Ew2gsr xSYgI84reXQeXw/mlsSVGT6v3xO4hp6bPuTSG9nuBmucxdT6LEt+w3Robnt8YDdVsSOt7 fyW+MBbkCwgRar7Vid7BAaXUbcSGUuAKGTsdOQAle/9ewmdjF7k/D2FKBAptovguDjpWc YG8y4DEYbQToNIL7GNt58JQu2a1ejbQH2t6A84kc9WZsKZ/IVMZbUXNpEYvaIAaHzWUOA faJCv0F+F43aON6vt8PDbLgwSETVS/oh3n6iYBcE2cCowdL0P/7yS3QRyVgw7kh5raw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=agOxSqvp; arc=none smtp.remote-ip=74.125.82.42 Received: from mail-dl1-f42.google.com (mail-dl1-f42.google.com [74.125.82.42]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BEF9060A3814 for ; Wed, 11 Nov 2026 06:57:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BEF9060A3814 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=agOxSqvp Received: by mail-dl1-f42.google.com with SMTP id a92af1059eb24-1b244fb7fffso3533182c88.1 for ; Tue, 10 Nov 2026 22:57:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1794380227; x=1794985027; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=lZaigarthkYfk+LJ/id0he7EntFXTEZZC4zUNeoO63c=; b=agOxSqvp1p3il60geexOXuGgwctrpHH59Nsqf8JNtRKhWnhpb9lxL229fRj6DlFs1N fgol9Txgzo5sV4VeOcDRuoUM9sAxxoIBOdd9gaXJBA/p2l5vEBrWaOVqoBR9NtYLWmum kANp6LqWF5ZmoBAZk/iQICAD1eR4jyIlRXDWWyWYH5kxFp9PvDOewjtGghIpntRSgWq9 PFjaOdKTezQlCykd4yHmbxXWPqe8ogX7Rfg0athXtAcr65TNreQVlQJFo5cGTbvYnGVU S3uTL3d+Ya4JxPQ100M5MbF2EK9+igSP8qvUNaVYWsZb6Mw9wwHtQVFkqv2JqlilooTn vPzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794380227; x=1794985027; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=lZaigarthkYfk+LJ/id0he7EntFXTEZZC4zUNeoO63c=; b=lfmd2F3mnhiflIwKu0JbmMVyLwSWzb1V+QaFCpkY+lSCnMLnG+93ytTQ637eC9GnR0 gp71yYO1mhHTKRWBd8Wwoq/x7n4dwJeFo2VZ6ZZ9i/zQXIyFhy4mZ+1gkI9TYjNirrOa pDS0KlsylnuPiUoVMuMDPPMzaj5NrJzmDhJVQPYAEUeLKdUt8SNLpK3xT0A+ddyfCzM+ QiQurWoPnyCqBtLXlmis6oIH0PVpDOXj13H9+ZN8Ip9BnEiLnb1SmbNq0AxBmYuFuzOi RmJOa0avqBEt20Qc47k6mPt9CUzDwLkEqas5pokGXV5IToxTwfH9SNZX4JJJOR37nvCe o9jw== X-Forwarded-Encrypted: i=1; AL+hErFeNi6z6XoXnsEkjgQcnoRSEfCGWjiMdCza0Fq/zl5I1degqH0Hh7d9qE3Q8bERqJ45aA63kph+sFZ9TA8=@vger.kernel.org X-Gm-Message-State: APuU4Z/BK+4gJoMVSF2XyTlvfb3PYm3KyXN+O0ot3has+nPFnCbOClzZ vM3ml2juHWhXjI/d0inhpBMqSjcir4LrrHH2aYHMsr9OURFAl0KmYpcI X-Gm-Gg: AYBFou1U2miQdTiPfM8ZM6LKk+7/TXfqSIGS9MWDCdaMY0QWCq5izkMaenuYM/3dVc/ /mGaEtjcciy6wGaug5N4zh5Ioj9yiyXqi9n7sN9c4tQMHDwjgiCEe2iQSojxMKGcsYv2Xy/NWCH +9kZ29175lvRJnSRlYyE0yTnVz1jTTV9cZKstc3x0baHLwZQrO4BphxGWbXDanHdDCKNXsqaFyx /fkz3Z2ZjA940C8dRBiFbr5RtsPh1vH6RgbWZ4JPp3C6OcMJGoQXD/sTduEkG3z1eahaIVHpTI5 ZY28vASALruZcl+lI9LXL3PmUhLREi8/hcTVYJOfXN9Z+mpEe/Ad0juXwkWP2QdV7o50VlG8uob YDR9bSd6E89jWA6QdN3FYWEfozir1hdJQmmjhqyxRtaQxnhBzqY7kAAldT/pYpHk+FyvBn/N24c 4w/IO55OrMV6FZ8zS854gdqhTjnUVXuqZtz3k5WiefNwf4gyDD+7xy2OAWbE2WgLyVojpP6nOG7 VdLlPzTVjfaJBcT3F5ubvbtKvbhUqtFbHoFNq8lraqJDDJBEFWvmx52KglE9dqizVSKkjRyOK8q 4fssuUAZQqUyM35RV9iPAl0ELvX5SNW3e68w9iJPrkriDGjXI+OQIzl+KJ0zkQZmUwK9801eZSr JHFJoPfMaSHZQEHpkgQ== X-Received: by 2002:a05:7022:ea4a:b0:1a3:9936:d11e with SMTP id a92af1059eb24-1b3c034aff7mr1595237c88.41.1794380226714; Tue, 10 Nov 2026 22:57:06 -0800 (PST) Received: from dtor-ws.sjc.corp.google.com ([2a00:79e0:2ebe:8:311a:ad7a:93f8:96c8]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1b3b5b11435sm13858121c88.4.2026.11.10.22.57.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Nov 2026 22:57:05 -0800 (PST) From: Dmitry Torokhov Date: Tue, 10 Nov 2026 22:48:25 -0800 Subject: [PATCH v2 27/33] HID: logitech-hidpp: store device serial as a byte array X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-hid-logitech-hidpp-v2-27-30743e91d83b@gmail.com> References: <20261110-hid-logitech-hidpp-v2-0-30743e91d83b@gmail.com> In-Reply-To: <20261110-hid-logitech-hidpp-v2-0-30743e91d83b@gmail.com> To: Jiri Kosina , Benjamin Tissoires , Gideon Heinz Cc: =?utf-8?q?Filipe_La=C3=ADns?= , Bastien Nocera , Hans de Goede , Edwin Velds , Stuart Hayhurst , Andrey Smirnov , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: b4 0.17-dev-e56a4 Device serial numbers are read from 4-byte protocol payloads only to be formatted as raw byte sequences with %4phD. Storing them as u32 requires unaligned pointer casts and dereferences that depend on endian-neutral memory layout, and the FAP-based serial helper reads from the RAP union member instead of the matching FAP payload. Represent device serial numbers as 4-byte arrays, copy the payload bytes with a fixed serial length constant, and read the FAP device information response from the FAP payload directly. Tested-by: Gideon Heinz Signed-off-by: Dmitry Torokhov --- drivers/hid/hid-logitech-hidpp.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c index df0bcaaf8647..181b791b3e0c 100644 --- a/drivers/hid/hid-logitech-hidpp.c +++ b/drivers/hid/hid-logitech-hidpp.c @@ -48,6 +48,7 @@ MODULE_PARM_DESC(disable_tap_to_click, #define HIDPP_REPORT_SHORT_LENGTH 7 #define HIDPP_REPORT_LONG_LENGTH 20 #define HIDPP_REPORT_VERY_LONG_MAX_LENGTH 64 +#define HIDPP_SERIAL_LENGTH 4 #define HIDPP_REPORT_SHORT_SUPPORTED BIT(0) #define HIDPP_REPORT_LONG_SUPPORTED BIT(1) @@ -898,7 +899,8 @@ static char *hidpp_unifying_get_name(struct hidpp_device *hidpp_dev) return name; } -static int hidpp_unifying_get_serial(struct hidpp_device *hidpp, u32 *serial) +static int hidpp_unifying_get_serial(struct hidpp_device *hidpp, + u8 serial[HIDPP_SERIAL_LENGTH]) { struct hidpp_report response; int ret; @@ -912,11 +914,7 @@ static int hidpp_unifying_get_serial(struct hidpp_device *hidpp, u32 *serial) if (ret) return ret; - /* - * We don't care about LE or BE, we will output it as a string - * with %4phD, so we need to keep the order. - */ - *serial = *((u32 *)&response.rap.params[1]); + memcpy(serial, &response.rap.params[1], HIDPP_SERIAL_LENGTH); return 0; } @@ -924,14 +922,14 @@ static int hidpp_unifying_init(struct hidpp_device *hidpp) { struct hid_device *hdev = hidpp->hid_dev; const char *name; - u32 serial; + u8 serial[HIDPP_SERIAL_LENGTH]; int ret; - ret = hidpp_unifying_get_serial(hidpp, &serial); + ret = hidpp_unifying_get_serial(hidpp, serial); if (ret) return ret; - snprintf(hdev->uniq, sizeof(hdev->uniq), "%4phD", &serial); + snprintf(hdev->uniq, sizeof(hdev->uniq), "%4phD", serial); dbg_hid("HID++ Unifying: Got serial: %s\n", hdev->uniq); name = hidpp_unifying_get_name(hidpp); @@ -1031,7 +1029,8 @@ static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp) #define CMD_GET_DEVICE_INFO 0x00 -static int hidpp_get_serial(struct hidpp_device *hidpp, u32 *serial) +static int hidpp_get_serial(struct hidpp_device *hidpp, + u8 serial[HIDPP_SERIAL_LENGTH]) { struct hidpp_report response; u8 feature_index; @@ -1048,22 +1047,21 @@ static int hidpp_get_serial(struct hidpp_device *hidpp, u32 *serial) if (ret) return ret; - /* See hidpp_unifying_get_serial() */ - *serial = *((u32 *)&response.rap.params[1]); + memcpy(serial, &response.fap.params[1], HIDPP_SERIAL_LENGTH); return 0; } static int hidpp_serial_init(struct hidpp_device *hidpp) { struct hid_device *hdev = hidpp->hid_dev; - u32 serial; + u8 serial[HIDPP_SERIAL_LENGTH]; int ret; - ret = hidpp_get_serial(hidpp, &serial); + ret = hidpp_get_serial(hidpp, serial); if (ret) return ret; - snprintf(hdev->uniq, sizeof(hdev->uniq), "%4phD", &serial); + snprintf(hdev->uniq, sizeof(hdev->uniq), "%4phD", serial); dbg_hid("HID++ DeviceInformation: Got serial: %s\n", hdev->uniq); return 0; -- 2.56.0.542.g3ef89b7020-goog