From patchwork Tue Sep 22 10:42:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai-Heng Feng X-Patchwork-Id: 1368971 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4BwdF44r1cz9sRf; Tue, 22 Sep 2020 20:43:04 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1kKflE-00033C-0C; Tue, 22 Sep 2020 10:43:00 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kKflC-000336-Jb for kernel-team@lists.ubuntu.com; Tue, 22 Sep 2020 10:42:58 +0000 Received: from 61-220-137-37.hinet-ip.hinet.net ([61.220.137.37] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kKflB-0001fF-U0 for kernel-team@lists.ubuntu.com; Tue, 22 Sep 2020 10:42:58 +0000 From: Kai-Heng Feng To: kernel-team@lists.ubuntu.com Subject: [SRU] [G/Unstable/OEM-5.6] [PATCH 0/1] Enable LTR for endpoints behind VMD Date: Tue, 22 Sep 2020 18:42:53 +0800 Message-Id: <20200922104255.24902-1-kai.heng.feng@canonical.com> X-Mailer: git-send-email 2.17.1 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" BugLink: https://bugs.launchpad.net/bugs/1896598 [Impact] PCIe links behind VMD may not be able to reach ASPM L1.2, because PCIe Link Tolenrence Reporting doesn't get programmed with a sensible value. [Fix] Temporarily hardcode LTR value, which is used by Windows, for NVMe devices behind VMD. [Test] With the patch applied, PCIe links can reach ASPM L1.2, hence the entire Intel SoC can reach deeper power saving state. [Regression Potential] This patch targets specifically Intel Tigerlake VMD bridges, so there won't be any regression since they are not on the market yet. Kai-Heng Feng (1): UBUNTU: SAUCE: PCI/ASPM: Enable LTR for endpoints behind VMD drivers/pci/quirks.c | 49 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-)