From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CB705FA0C4D for ; Wed, 15 Apr 2026 08:38:15 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 797896F7D7; Wed, 15 Apr 2026 08:38:15 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id ek7F3Izu7dnk; Wed, 15 Apr 2026 08:38:14 +0000 (UTC) X-Comment: SPF check N/A for local connections - client-ip=140.211.166.142; helo=lists1.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver= DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 1E78C6F7D2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osuosl.org; s=default; t=1776242294; bh=o2NGFgfPn6EU9KE6meJqj6NiC/YABatJ5iB6FIwagpg=; h=Date:To:Cc:References:From:In-Reply-To:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=UeXhdPhe/mOfe6auj95NZtLRE02Vi9hKZoHEl2MyQTTZ6Ry2OxdNB1HA+YVnWJD7j ka2A3Seeg3SJc0TMwKg1ul49rXsdklY+7Q9v9BBo+607RJ9jNkyi3ZkAQOdEO+W+1R RkmNGIQpXphCKU8WS4Q7FSaeMYxF/6ETsi/550bhFEkez+Oujvkvf/2DqFkJUWWoQb p6XbmSwcQfcD/Q28KJEFHT2HpVVx95kVyPpJcTx00mEiw/xN2zXcKY0ep+IiN0K8+Y NPwAnChyQfS5AFWHmgz+qh6ZVsConCnrFhZQN/sZnq7EYRLTBGoW3EortfqGIhDLUu jcjTJqrz5MiAg== Received: from lists1.osuosl.org (lists1.osuosl.org [140.211.166.142]) by smtp3.osuosl.org (Postfix) with ESMTP id 1E78C6F7D2; Wed, 15 Apr 2026 08:38:14 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [IPv6:2605:bc80:3010::136]) by lists1.osuosl.org (Postfix) with ESMTP id 3326F237 for ; Wed, 15 Apr 2026 08:38:13 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 248B16F77A for ; Wed, 15 Apr 2026 08:38:13 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id OQScOVT5u3AU for ; Wed, 15 Apr 2026 08:38:12 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=192.198.163.9; helo=mgamail.intel.com; envelope-from=faizal.abdul.rahim@linux.intel.com; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp3.osuosl.org C80BB6F7D2 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org C80BB6F7D2 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by smtp3.osuosl.org (Postfix) with ESMTPS id C80BB6F7D2 for ; Wed, 15 Apr 2026 08:38:11 +0000 (UTC) X-CSE-ConnectionGUID: 9IxUt9jUR228+y8BUme/HQ== X-CSE-MsgGUID: GfbKZs5aRqaGWOffKL5nbw== X-IronPort-AV: E=McAfee;i="6800,10657,11759"; a="87914970" X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="87914970" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2026 01:38:11 -0700 X-CSE-ConnectionGUID: T4ArbB4xS227m+HZRmDGeQ== X-CSE-MsgGUID: DIzosRa5RXmyFA6P+VAa2g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="223857364" Received: from mohdfai2-mobl.gar.corp.intel.com (HELO [10.247.20.182]) ([10.247.20.182]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2026 01:38:06 -0700 Message-ID: Date: Wed, 15 Apr 2026 16:37:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Simon Horman , khai.wen.tan@linux.intel.com Cc: anthony.l.nguyen@intel.com, przemyslaw.kitszel@intel.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, faizal.abdul.rahim@intel.com, hector.blanco.alcaine@intel.com, hong.aun.looi@intel.com, khai.wen.tan@intel.com References: <20260409072747.217836-1-khai.wen.tan@linux.intel.com> <20260413145215.718532-1-horms@kernel.org> Content-Language: en-US From: "Abdul Rahim, Faizal" In-Reply-To: <20260413145215.718532-1-horms@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776242292; x=1807778292; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=+E24YrPrdzJ1ya9Ikgcx0KKiXJaJ4AYDwwErZxu5fG0=; b=WB4Rty8REWJYIHweme5mBnXmrcnwcaDDRIPu+fkQKIh74+9fG6jC9hzR yh7ce+lRmUtO88cZq7GkKdTYEjJD2mmTCj3tNJS7DwNzqzvvPscSn/kCC 9/2tNjJV45rhGjt3sDEkYLmSL2MHqEKk98LYlRDN4npkuiJdvLKATrgIh rX8KVDEfVW9LPBRFYrKTLACmpAG9vVVY+Ojfr5pyzj6bMYidIAuyWwurg iARpIEQ9GXrlfCaWjSDcEWlc65I9/qELy7hP0hWqkcyRp4cnjbXRJJ+hv CyDFw1sAeALbiRbfk+0M6gN8W+f20liplklUhLxSwutwUhj3UuRoPCzVo A==; X-Mailman-Original-Authentication-Results: smtp3.osuosl.org; dmarc=none (p=none dis=none) header.from=linux.intel.com X-Mailman-Original-Authentication-Results: smtp3.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=WB4Rty8R Subject: Re: [Intel-wired-lan] [PATCH iwl-next 1/1] igc: add support for forcing link speed without autonegotiation X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" On 13/4/2026 10:52 pm, Simon Horman wrote: > From: 'Simon Horman' > > This is an AI-generated review of your patch. The human sending this > email has considered the AI review valid, or at least plausible. > Full review at: https://sashiko.dev > --- > igc: add support for forcing link speed without autonegotiation > > This commit allows forcing 10/100 Mb/s link speed and duplex settings via > ethtool when autonegotiation is disabled. It configures the MAC CTRL and > PHY registers to bypass autonegotiation and apply the requested settings. > >> diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c >> index 0122009bedd03..e14771532dad8 100644 >> --- a/drivers/net/ethernet/intel/igc/igc_ethtool.c >> +++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c > [ ... ] >> +static int igc_handle_autoneg_disabled(struct net_device *netdev, u32 speed, >> + u8 duplex) >> +{ >> + struct igc_adapter *adapter = netdev_priv(netdev); >> + struct igc_mac_info *mac = &adapter->hw.mac; >> + enum igc_forced_speed_duplex forced_speed_duplex; >> >> + switch (speed) { >> + case SPEED_10: >> + forced_speed_duplex = (duplex == DUPLEX_FULL) ? IGC_FORCED_10F : IGC_FORCED_10H; >> + break; >> + case SPEED_100: >> + forced_speed_duplex = (duplex == DUPLEX_FULL) ? IGC_FORCED_100F : IGC_FORCED_100H; >> + break; > > Does forcing a half-duplex configuration here also require setting flow > control to none (e.g., hw->fc.requested_mode = igc_fc_none)? > >> diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ethernet/intel/igc/igc_mac.c >> index 7ac6637f8db73..16b0f2db06896 100644 >> --- a/drivers/net/ethernet/intel/igc/igc_mac.c >> +++ b/drivers/net/ethernet/intel/igc/igc_mac.c >> @@ -452,7 +452,7 @@ s32 igc_config_fc_after_link_up(struct igc_hw *hw) >> * so we had to force link. In this case, we need to force the >> * configuration of the MAC to match the "fc" parameter. >> */ >> - if (mac->autoneg_failed) >> + if (mac->autoneg_failed || !mac->autoneg_enabled) >> ret_val = igc_force_mac_fc(hw); > > If mac->autoneg_enabled is false, igc_force_mac_fc() will configure the MAC > using the existing hw->fc.current_mode. If current_mode defaults to full flow > control, this will enable PAUSE frames. > > Since autonegotiation is disabled, the MII status check further down in this > same function will fail and return early: > > drivers/net/ethernet/intel/igc/igc_mac.c:igc_config_fc_after_link_up() { > ... > if (!(mii_status_reg & MII_SR_AUTONEG_COMPLETE)) { > hw_dbg("Copper PHY and Auto Neg has not completed.\n"); > goto out; > } > ... > } > > This early return skips the half-duplex safety check at the end of > igc_config_fc_after_link_up() which would normally clear the flow control > settings: > > drivers/net/ethernet/intel/igc/igc_mac.c:igc_config_fc_after_link_up() { > ... > if (duplex == HALF_DUPLEX) > hw->fc.current_mode = igc_fc_none; > > ret_val = igc_force_mac_fc(hw); > ... > } > > Does this leave the MAC incorrectly configured to send and receive PAUSE > frames on a half-duplex link, violating the IEEE 802.3 specification? Hi Simon, Thanks for the review. Yes, you're right, I missed that interaction. I’ll update the code to also set the following in igc_handle_autoneg_disabled() when forcing half‑duplex: hw->fc.requested_mode = igc_fc_none I’ll test it and, if everything looks good, send out v2. Thanks again!