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_PASS,URIBL_BLOCKED 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 BB58BC43144 for ; Tue, 26 Jun 2018 10:07:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7566126881 for ; Tue, 26 Jun 2018 10:07:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7566126881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rjwysocki.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934045AbeFZKHU (ORCPT ); Tue, 26 Jun 2018 06:07:20 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:60435 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932189AbeFZKHS (ORCPT ); Tue, 26 Jun 2018 06:07:18 -0400 Received: from 79.184.255.183.ipv4.supernova.orange.pl (79.184.255.183) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id ccfaeef6769110af; Tue, 26 Jun 2018 12:07:17 +0200 From: "Rafael J. Wysocki" To: Linux PCI Cc: n0000b.n000b@gmail.com, Bjorn Helgaas , Mika Westerberg , LKML , Linux ACPI , Linux PM , Lukas Wunner Subject: [PATCH] PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM Date: Tue, 26 Jun 2018 12:06:01 +0200 Message-ID: <35587465.8Nave9aG7d@aspire.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki It is reported that commit c62ec4610c40 (PM / core: Fix direct_complete handling for devices with no callbacks) introduced a system suspend regression on Samsung 305V4A by allowing a PCI bridge (not a PCIe port) to stay in D3 over suspend-to-RAM, which is a side effect of setting power.direct_complete for the children of that bridge that have no PM callbacks. On the majority of systems PCI bridges are not allowed to be runtime-suspended (the power/control sysfs attribute is set to "on" for them by default), but user space can change that setting and if it does so and a given bridge has no children with PM callbacks, the direct_complete optimization will be applied to it and it will stay in suspend over system suspend. Apparently, that confuses the platform firmware on the affected machine and that may very well happen elsewhere, so avoid the direct_complete optimization for PCI bridges with no drivers (if there is a driver, it should take care of the PM handling) on suspend-to-RAM altogether (that should not matter for suspend-to-idle as platform firmware is not involved in it). Fixes: c62ec4610c40 (PM / core: Fix direct_complete handling for devices with no callbacks) Link: https://bugzilla.kernel.org/show_bug.cgi?id=199941 Reported-by: n0000b.n000b@gmail.com Tested-by: n0000b.n000b@gmail.com Signed-off-by: Rafael J. Wysocki --- drivers/pci/pci-acpi.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: linux-pm/drivers/pci/pci-acpi.c =================================================================== --- linux-pm.orig/drivers/pci/pci-acpi.c +++ linux-pm/drivers/pci/pci-acpi.c @@ -638,6 +638,14 @@ static bool acpi_pci_need_resume(struct if (acpi_target_system_state() == ACPI_STATE_S0) return false; + /* + * In some cases (eg. Samsung 305V4A) leaving a bridge in suspend + * confuses the platform firmware, so avoid doing that, unless the + * bridge has a driver that should take care of PM handling. + */ + if (pci_is_bridge(dev) && !dev->driver) + return true; + return !!adev->power.flags.dsw_present; }