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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D4E7C48BD6 for ; Tue, 25 Jun 2019 10:25:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D653214DA for ; Tue, 25 Jun 2019 10:25:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731906AbfFYKZG (ORCPT ); Tue, 25 Jun 2019 06:25:06 -0400 Received: from mga14.intel.com ([192.55.52.115]:18304 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731879AbfFYKZE (ORCPT ); Tue, 25 Jun 2019 06:25:04 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jun 2019 03:25:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,415,1557212400"; d="scan'208";a="245028430" Received: from sneftin-mobl1.ger.corp.intel.com (HELO [10.185.23.132]) ([10.185.23.132]) by orsmga001.jf.intel.com with ESMTP; 25 Jun 2019 03:25:00 -0700 Subject: Re: [Intel-wired-lan] Opportunistic S0ix blocked by e1000e when ethernet is in use To: Kai-Heng Feng Cc: jeffrey.t.kirsher@intel.com, intel-wired-lan@lists.osuosl.org, Anthony Wong , linux-kernel References: <074E1145-A512-4835-9A6D-8FB6634DBD3C@canonical.com> <95f88f45-fd6c-52e4-de8c-2db1b4c6c04e@intel.com> From: "Neftin, Sasha" Message-ID: Date: Tue, 25 Jun 2019 13:25:00 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/24/2019 18:06, Kai-Heng Feng wrote: > at 19:56, Neftin, Sasha wrote: > >> On 6/24/2019 10:03, Kai-Heng Feng wrote: >>> Hi Jeffrey, >>> at 19:08, Kai-Heng Feng wrote: >>>> Hi Jeffrey, >>>> >>>> There are several platforms that uses e1000e can’t enter >>>> Opportunistic S0ix (PC10) when the ethernet has a link partner. >>>> >>>> This behavior also exits in out-of-tree e1000e driver 3.4.2.1, but >>>> seems like 3.4.2.3 fixes the issue. >>>> >>>> A quick diff between the two versions shows that this code section >>>> may be our solution: >>>> >>>>         /* Read from EXTCNF_CTRL in e1000_acquire_swflag_ich8lan >>>> function >>>>          * may occur during global reset and cause system hang. >>>>          * Configuration space access creates the needed delay. >>>>          * Write to E1000_STRAP RO register >>>> E1000_PCI_VENDOR_ID_REGISTER value >>>>          * insures configuration space read is done before global >>>> reset. >>>>          */ >>>>         pci_read_config_word(hw->adapter->pdev, >>>> E1000_PCI_VENDOR_ID_REGISTER, >>>>                              &pci_cfg); >>>>         ew32(STRAP, pci_cfg); >>>>         e_dbg("Issuing a global reset to ich8lan\n"); >>>>         ew32(CTRL, (ctrl | E1000_CTRL_RST)); >>>>         /* cannot issue a flush here because it hangs the hardware */ >>>>         msleep(20); >>>> >>>>         /* Configuration space access improve HW level time sync >>>> mechanism. >>>>          * Write to E1000_STRAP RO register >>>> E1000_PCI_VENDOR_ID_REGISTER >>>>          * value to insure configuration space read is done >>>>          * before any access to mac register. >>>>          */ >>>>         pci_read_config_word(hw->adapter->pdev, >>>> E1000_PCI_VENDOR_ID_REGISTER, >>>>                              &pci_cfg); >>>>         ew32(STRAP, pci_cfg); >>> Turns out the "extra sauce” is not this part, it’s called “Dynamic >>> LTR support”. >>> >> >>>> Is there any plan to support this in the upstream kernel? >>> Is there any plan to support Dynamic LTR in upstream e1000e? >> Dynamic LTR is not stable solution. So, we can not put this solution >> to upstream. I hope we will be able to fix this in HW for a future >> projects. > > Does this mean current generation hardware won’t get the fix? Current HW have a limitation. Please, try follow workaround on your platform: echo 3 > /sys/kernel/debug/pmc_core/ltr_ignore > >> S0ix support is under discussion with our architecture. We will try >> enable S0ix in our e1000e OOT driver as first step. > > Is it possible to add Dynamic LTR as an option so users and downstream > distros can still benefit from it? As I said before, this is not a stable solution. No guarantee that HW will work as properly. > > Kai-Heng > >>> Kai-Heng >>>> Kai-Heng >>> _______________________________________________ >>> Intel-wired-lan mailing list >>> Intel-wired-lan@osuosl.org >>> https://lists.osuosl.org/mailman/listinfo/intel-wired-lan >> >> Thanks >> Sasha > >