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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 25B73C4646B for ; Mon, 24 Jun 2019 23:09:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F218520679 for ; Mon, 24 Jun 2019 23:09:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728058AbfFXXJl (ORCPT ); Mon, 24 Jun 2019 19:09:41 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:58549 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728045AbfFXXJl (ORCPT ); Mon, 24 Jun 2019 19:09:41 -0400 Received: from 79.184.254.216.ipv4.supernova.orange.pl (79.184.254.216) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.267) id d4c091cf0ca37d7c; Tue, 25 Jun 2019 01:09:37 +0200 From: "Rafael J. Wysocki" To: Jon Hunter Cc: Linux PCI , Bjorn Helgaas , Linux PM , Linux ACPI , LKML , Mika Westerberg , Keith Busch , Kai-Heng Feng , linux-tegra Subject: Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle Date: Tue, 25 Jun 2019 01:09:36 +0200 Message-ID: <2287147.DxjcvLeq6l@kreacher> In-Reply-To: References: <1668247.RaJIPSxJUN@kreacher> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tuesday, June 25, 2019 12:20:26 AM CEST Rafael J. Wysocki wrote: > On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki wrote: > > > > On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter wrote: > > > > > > Hi Rafael, > > > > > > On 13/06/2019 22:59, Rafael J. Wysocki wrote: > > > > From: Rafael J. Wysocki > > > > > > > > Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue") > > > > attempted to avoid a problem with devices whose drivers want them to > > > > stay in D0 over suspend-to-idle and resume, but it did not go as far > > > > as it should with that. > > > > > > > > Namely, first of all, the power state of a PCI bridge with a > > > > downstream device in D0 must be D0 (based on the PCI PM spec r1.2, > > > > sec 6, table 6-1, if the bridge is not in D0, there can be no PCI > > > > transactions on its secondary bus), but that is not actively enforced > > > > during system-wide PM transitions, so use the skip_bus_pm flag > > > > introduced by commit d491f2b75237 for that. > > > > > > > > Second, the configuration of devices left in D0 (whatever the reason) > > > > during suspend-to-idle need not be changed and attempting to put them > > > > into D0 again by force is pointless, so explicitly avoid doing that. > > > > > > > > Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue") > > > > Reported-by: Kai-Heng Feng > > > > Signed-off-by: Rafael J. Wysocki > > > > Reviewed-by: Mika Westerberg > > > > Tested-by: Kai-Heng Feng > > > > > > I have noticed a regression in both the mainline and -next branches on > > > one of our boards when testing suspend. The bisect is point to this > > > commit and reverting on top of mainline does fix the problem. So far I > > > have not looked at this in close detail but kernel log is showing ... > > > > Can you please collect a log like that, but with dynamic debug in > > pci-driver.c enabled? > > > > Note that reverting this commit is rather out of the question, so we > > need to get to the bottom of the failure. > > I suspect that there is a problem with the pm_suspend_via_firmware() > check which returns 'false' on the affected board, but the platform > actually removes power from devices left in D0 during suspend. > > I guess it would be more appropriate to check something like > pm_suspend_no_platform() which would return 'true' in the > suspend-to-idle patch w/ ACPI. So I wonder if the patch below makes any difference? --- drivers/pci/pci-driver.c | 8 ++++---- include/linux/suspend.h | 26 ++++++++++++++++++++++++-- kernel/power/suspend.c | 3 +++ 3 files changed, 31 insertions(+), 6 deletions(-) Index: linux-pm/include/linux/suspend.h =================================================================== --- linux-pm.orig/include/linux/suspend.h +++ linux-pm/include/linux/suspend.h @@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspen extern unsigned int pm_suspend_global_flags; -#define PM_SUSPEND_FLAG_FW_SUSPEND (1 << 0) -#define PM_SUSPEND_FLAG_FW_RESUME (1 << 1) +#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0) +#define PM_SUSPEND_FLAG_FW_RESUME BIT(1) +#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2) static inline void pm_suspend_clear_flags(void) { @@ -227,6 +228,11 @@ static inline void pm_set_resume_via_fir pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME; } +static inline void pm_set_suspend_no_platform(void) +{ + pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM; +} + /** * pm_suspend_via_firmware - Check if platform firmware will suspend the system. * @@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmwar return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME); } +/** + * pm_suspend_no_platform - Check if platform may change device power states. + * + * To be called during system-wide power management transitions to sleep states + * or during the subsequent system-wide transitions back to the working state. + * + * Return 'true' if the power states of devices remain under full control of the + * kernel throughout the system-wide suspend and resume cycle in progress (that + * is, if a device is put into a certain power state during suspend, it can be + * expected to remain in that state during resume). + */ +static inline bool pm_suspend_no_platform(void) +{ + return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM); +} + /* Suspend-to-idle state machnine. */ enum s2idle_states { S2IDLE_STATE_NONE, /* Not suspended/suspending. */ Index: linux-pm/kernel/power/suspend.c =================================================================== --- linux-pm.orig/kernel/power/suspend.c +++ linux-pm/kernel/power/suspend.c @@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_st pm_suspend_target_state = state; + if (state == PM_SUSPEND_TO_IDLE) + pm_set_suspend_no_platform(); + error = platform_suspend_begin(state); if (error) goto Close; Index: linux-pm/drivers/pci/pci-driver.c =================================================================== --- linux-pm.orig/drivers/pci/pci-driver.c +++ linux-pm/drivers/pci/pci-driver.c @@ -870,7 +870,7 @@ static int pci_pm_suspend_noirq(struct d pci_dev->bus->self->skip_bus_pm = true; } - if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) { + if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) { dev_dbg(dev, "PCI PM: Skipped\n"); goto Fixup; } @@ -925,10 +925,10 @@ static int pci_pm_resume_noirq(struct de /* * In the suspend-to-idle case, devices left in D0 during suspend will * stay in D0, so it is not necessary to restore or update their - * configuration here and attempting to put them into D0 again may - * confuse some firmware, so avoid doing that. + * configuration here and attempting to put them into D0 again is + * pointless, so avoid doing that. */ - if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware()) + if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform())) pci_pm_default_resume_early(pci_dev); pci_fixup_device(pci_fixup_resume_early, pci_dev);