From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F195F28134C; Sat, 14 Feb 2026 21:25:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771104316; cv=none; b=dM+hWhoZjd+W+Q6OIkp6SV+ZA1gAiuK5y8GWX4FosiMIMuZgq9Z0JZ7Ro814iVkdOpHxOhU76A8SDdx05ATQTDxXDhDPc4YAjnpc6tScHWnMnmW40Eob5KUySO5y/WSuZ+iRLhCJw/i/VofuAcu3UMPh6efAnlyJKfrzNl+3BZI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771104316; c=relaxed/simple; bh=MWhNcefrLhC3Rj5lpUlVUCHDE3IjMVQY4NNTvDIKqyk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=XkzP4mnYpucZc/ukxe/TCWdWnL1Noti221JdP+k9Ah5aeAJq7n9pdky9c0JtWEFuhD+G9orF06+mkXrgPuuMyD2+djH2bGm87jYiVneBzmHZt5E4UR5+a/u50r02ne6cNFWSMn6+2VHqYsHIvzign6bqb4NgKAgB4QrOSpJBxiQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=u4xRdAde; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="u4xRdAde" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17A46C19423; Sat, 14 Feb 2026 21:25:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771104315; bh=MWhNcefrLhC3Rj5lpUlVUCHDE3IjMVQY4NNTvDIKqyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u4xRdAdecxoJBDOrws3J/oiJFENuuDp86YX7JpBEAnLV/TUHukRRbQ9wcuLajDfgU LC4tl6pYD1X6kLVfPKHxPs7HG5RMEJA+7N0esTZN/7SaHlpfEnGgARxKPm2VL51Vk8 0oifNRn/fBHcRpnPtX+k6qaVYGNQN32jmzDnHTaM31JuIB3Vcur/o8fsvCsIRgRroj 41xEjSmR7r7KNUdL+tFUdTrex5YsIZTDkjwz1RfsCXZu6NfgP/yZh3BxkUdnXy1uNZ OzobJrWE4zKoiL9H/eLXSgBz6wq9BcywdZUC33EZnXfNjyj03h8jHx7xMkskLoy6uS WlIt5zzjIe83A== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Hsiu-Ming Chang , Ping-Ke Shih , Sasha Levin , linux-wireless@vger.kernel.org Subject: [PATCH AUTOSEL 6.19-6.6] wifi: rtw88: rtw8821cu: Add ID for Mercusys MU6H Date: Sat, 14 Feb 2026 16:22:36 -0500 Message-ID: <20260214212452.782265-11-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260214212452.782265-1-sashal@kernel.org> References: <20260214212452.782265-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.19 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Hsiu-Ming Chang [ Upstream commit 77653c327e11c71c5363b18a53fbf2b92ed21da4 ] Add support for Mercusys MU6H AC650 High Gain Wireless Dual Band USB Adapter V1.30. It is based on RTL8811CU, usb device ID is 2c4e:0105. Signed-off-by: Hsiu-Ming Chang Acked-by: Ping-Ke Shih Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/20251205003245.5762-1-cges30901@gmail.com Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: ## Analysis: Adding USB Device ID for Mercusys MU6H to rtw8821cu driver ### Commit Message Analysis The commit adds a USB device ID (vendor: 0x2c4e, product: 0x0105) for the Mercusys MU6H AC650 High Gain Wireless Dual Band USB Adapter to the existing rtw8821cu driver. The device is based on the RTL8811CU chipset. ### Code Change Analysis The change is a **two-line addition** to the USB device ID table in `drivers/net/wireless/realtek/rtw88/rtw8821cu.c`: ```c { USB_DEVICE_AND_INTERFACE_INFO(0x2c4e, 0x0105, 0xff, 0xff, 0xff), .driver_info = (kernel_ulong_t)&(rtw8821c_hw_spec) }, /* Mercusys */ ``` This follows the exact same pattern as every other entry in the table (D-Link, Edimax, and the various Realtek-branded variants). The entry uses the same `rtw8821c_hw_spec` hardware specification structure, meaning the driver already fully supports this chipset — it just needs to know about this particular vendor/product ID combination. ### Classification This is a **new device ID addition** to an existing driver — one of the explicitly listed exceptions that IS appropriate for stable backporting. >From the stable rules: > **NEW DEVICE IDs (Very Common):** Adding PCI IDs, USB IDs, ACPI IDs, etc. to existing drivers. These are trivial one-line additions that enable hardware support. Rule: The driver must already exist in stable; only the ID is new. ### Risk Assessment - **Risk: Extremely low.** This is a pure data addition — a new entry in a USB ID matching table. It cannot affect any existing functionality. - **Scope: Minimal.** Two lines added, one file changed, no logic changes. - **Regression potential: Zero.** The new ID only matches a specific USB device (0x2c4e:0x0105). No other device is affected. ### User Impact - Users with this specific Mercusys MU6H adapter cannot use it at all without this ID entry. With the entry, the existing (and already working) rtw8821cu driver will automatically bind to the device. - This is a consumer WiFi adapter, so real users on stable kernels would benefit from this backport. ### Stability Indicators - Acked-by the Realtek maintainer (Ping-Ke Shih) - The pattern is identical to existing entries - The rtw88 driver and rtw8821cu sub-driver already exist in stable trees ### Dependencies - None. This is a completely self-contained change. ### Conclusion This is a textbook example of a device ID addition that should be backported to stable. It enables hardware support for a specific USB WiFi adapter using an already-existing, well-tested driver. The change is trivial, zero-risk, and directly benefits users who own this device. **YES** drivers/net/wireless/realtek/rtw88/rtw8821cu.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/wireless/realtek/rtw88/rtw8821cu.c b/drivers/net/wireless/realtek/rtw88/rtw8821cu.c index 7a0fffc359e25..8cd09d66655db 100644 --- a/drivers/net/wireless/realtek/rtw88/rtw8821cu.c +++ b/drivers/net/wireless/realtek/rtw88/rtw8821cu.c @@ -37,6 +37,8 @@ static const struct usb_device_id rtw_8821cu_id_table[] = { .driver_info = (kernel_ulong_t)&(rtw8821c_hw_spec) }, /* Edimax */ { USB_DEVICE_AND_INTERFACE_INFO(0x7392, 0xd811, 0xff, 0xff, 0xff), .driver_info = (kernel_ulong_t)&(rtw8821c_hw_spec) }, /* Edimax */ + { USB_DEVICE_AND_INTERFACE_INFO(0x2c4e, 0x0105, 0xff, 0xff, 0xff), + .driver_info = (kernel_ulong_t)&(rtw8821c_hw_spec) }, /* Mercusys */ {}, }; MODULE_DEVICE_TABLE(usb, rtw_8821cu_id_table); -- 2.51.0