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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 6A745C47404 for ; Mon, 7 Oct 2019 13:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BB582196E for ; Mon, 7 Oct 2019 13:24:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570454669; bh=VihV6dbAFqYapoc2NQzCD6WaB/LSQjIdFqbcjmbSvH4=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=FKAemGR0qzpYEyLQPpz1R/c6Xt0S/pfNRTqxgvSwuLu9J5fN4lB7w2d1gnFBGpDqK WcaHX/tR9bgLJdTOSEMFhs7T+vi23ElHaUfgdR8/M+ZBABrJIrkOaVhLTQXo54Dijm A9YP+DmBWYFxEqRhKFlLwWQ5/PKsF24iU9R/vaFw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727685AbfJGNY2 (ORCPT ); Mon, 7 Oct 2019 09:24:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:60484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727490AbfJGNY2 (ORCPT ); Mon, 7 Oct 2019 09:24:28 -0400 Received: from localhost (173-25-83-245.client.mchsi.com [173.25.83.245]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 57A5B2084D; Mon, 7 Oct 2019 13:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570454656; bh=VihV6dbAFqYapoc2NQzCD6WaB/LSQjIdFqbcjmbSvH4=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=zqA6UiTXH1B2jUHHJ7cyZ2HETPfjBI5GZ7X74v1prqwaIHNu2sNw+CCVDmfs4r24i dCWhA5QhGg7SpBELP4QjMEZc5I3exypt1HpSigICcpmCJLgE1fUwojjrefSUxT5SA9 2sj0tITXpHw7U4pvJFajGOQh2FmfyD1XXetT6BZo= Date: Mon, 7 Oct 2019 08:24:14 -0500 From: Bjorn Helgaas To: Dexuan Cui Cc: "lorenzo.pieralisi@arm.com" , "linux-pci@vger.kernel.org" , Michael Kelley , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "driverdev-devel@linuxdriverproject.org" , Sasha Levin , Haiyang Zhang , KY Srinivasan , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" , vkuznets , "marcelo.cerri@canonical.com" , Stephen Hemminger , "jackm@mellanox.com" Subject: Re: [PATCH v2] PCI: PM: Move to D0 before calling pci_legacy_resume_early() Message-ID: <20191007132414.GA19294@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Aug 14, 2019 at 01:06:55AM +0000, Dexuan Cui wrote: > > In pci_legacy_suspend_late(), the device state is moved to PCI_UNKNOWN. > > In pci_pm_thaw_noirq(), the state is supposed to be moved back to PCI_D0, > but the current code misses the pci_legacy_resume_early() path, so the > state remains in PCI_UNKNOWN in that path. As a result, in the resume > phase of hibernation, this causes an error for the Mellanox VF driver, > which fails to enable MSI-X because pci_msi_supported() is false due > to dev->current_state != PCI_D0: > > mlx4_core a6d1:00:02.0: Detected virtual function - running in slave mode > mlx4_core a6d1:00:02.0: Sending reset > mlx4_core a6d1:00:02.0: Sending vhcr0 > mlx4_core a6d1:00:02.0: HCA minimum page size:512 > mlx4_core a6d1:00:02.0: Timestamping is not supported in slave mode > mlx4_core a6d1:00:02.0: INTx is not supported in multi-function mode, aborting > PM: dpm_run_callback(): pci_pm_thaw+0x0/0xd7 returns -95 > PM: Device a6d1:00:02.0 failed to thaw: error -95 > > To be more accurate, the "resume" phase means the "thaw" callbacks which > run before the system enters hibernation: when the user runs the command > "echo disk > /sys/power/state" for hibernation, first the kernel "freezes" > all the devices and creates a hibernation image, then the kernel "thaws" > the devices including the disk/NIC, writes the memory to the disk, and > powers down. This patch fixes the error message for the Mellanox VF driver > in this phase. > > When the system starts again, a fresh kernel starts to run, and when the > kernel detects that a hibernation image was saved, the kernel "quiesces" > the devices, and then "restores" the devices from the saved image. In this > path: > device_resume_noirq() -> ... -> > pci_pm_restore_noirq() -> > pci_pm_default_resume_early() -> > pci_power_up() moves the device states back to PCI_D0. This path is > not broken and doesn't need my patch. > > Signed-off-by: Dexuan Cui This looks like a bugfix for 5839ee7389e8 ("PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()") so maybe it should be marked for stable as 5839ee7389e8 was? Rafael, could you confirm? > --- > > changes in v2: > Updated the changelog with more details. > > drivers/pci/pci-driver.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index 36dbe960306b..27dfc68db9e7 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -1074,15 +1074,16 @@ static int pci_pm_thaw_noirq(struct device *dev) > return error; > } > > - if (pci_has_legacy_pm_support(pci_dev)) > - return pci_legacy_resume_early(dev); > - > /* > * pci_restore_state() requires the device to be in D0 (because of MSI > * restoration among other things), so force it into D0 in case the > * driver's "freeze" callbacks put it into a low-power state directly. > */ > pci_set_power_state(pci_dev, PCI_D0); > + > + if (pci_has_legacy_pm_support(pci_dev)) > + return pci_legacy_resume_early(dev); > + > pci_restore_state(pci_dev); > > if (drv && drv->pm && drv->pm->thaw_noirq) > -- > 2.19.1 >