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 6D9BA37F008; Tue, 17 Mar 2026 16:45:18 +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=1773765918; cv=none; b=ELKgqUwAtIiVqR/AOUpHfBDwxFUk8klgBaeTpEoB8mvhYFriiBqtXRCpimO20qix0pVpUqJX5JePAGJbOdgblvUMX+lS1yLzQn9kpCTmFDzjERXd3Cz+m3rRMeAtU4vKZ43QOmcAZj+jvWGro2/Z0lvMnGxeQHXGk9pqTwEKEw0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773765918; c=relaxed/simple; bh=6OrhKCTjNiWnp2uay5W4KVmIHVfDrdX1SWN8XO8Xk7M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oXEiwVhnAhQnXbOsH0erorfI3mKSwsbGBgbYaX5tsBt95btn5dNqyQoZcdWEB0TC56Ajqb4xf8XCWTIN00CHdBsj3oZ0H9RsbAgpp6kPrUxiIw/OjaEg3CDaPg0vBSjO2SyATOR7SnbO3an98OunkRmJZF+btWvPaIJgIJHrSIE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dooTeG7Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dooTeG7Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFF49C4CEF7; Tue, 17 Mar 2026 16:45:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773765918; bh=6OrhKCTjNiWnp2uay5W4KVmIHVfDrdX1SWN8XO8Xk7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dooTeG7Yaeag8PE2evDXr08dqcg9zBPCNU1SaY0yjLEs3H/sjDaCP6e+Wwus9Rkrq HkfWRt7DdMTRJJa2QaVoxYko5kDH7ACMPUNXURvjeoskunap1pCMIaQdri6fHcHVHq 0uVmwVpk8ylMysaPxN9hGBdGgG3FtteriCZ52Aqs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oleksij Rempel , Jakub Kicinski Subject: [PATCH 6.19 124/378] net: usb: lan78xx: skip LTM configuration for LAN7850 Date: Tue, 17 Mar 2026 17:31:21 +0100 Message-ID: <20260317163011.578048281@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260317163006.959177102@linuxfoundation.org> References: <20260317163006.959177102@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleksij Rempel commit d9cc0e440f0664f6f3e2c26e39ab9dd5f3badba7 upstream. Do not configure Latency Tolerance Messaging (LTM) on USB 2.0 hardware. The LAN7850 is a High-Speed (USB 2.0) only device and does not support SuperSpeed features like LTM. Currently, the driver unconditionally attempts to configure LTM registers during initialization. On the LAN7850, these registers do not exist, resulting in writes to invalid or undocumented memory space. This issue was identified during a port to the regmap API with strict register validation enabled. While no functional issues or crashes have been observed from these invalid writes, bypassing LTM initialization on the LAN7850 ensures the driver strictly adheres to the hardware's valid register map. Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20260305143429.530909-4-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/lan78xx.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -3119,6 +3119,10 @@ static int lan78xx_init_ltm(struct lan78 int ret; u32 buf; + /* LAN7850 is USB 2.0 and does not support LTM */ + if (dev->chipid == ID_REV_CHIP_ID_7850_) + return 0; + ret = lan78xx_read_reg(dev, USB_CFG1, &buf); if (ret < 0) goto init_ltm_failed;