From: decui@microsoft.com (Dexuan Cui) Subject: [PATCH v2] PCI: PM: Move to D0 before calling pci_legacy_resume_early() Date: Wed, 14 Aug 2019 01:06:55 +0000 [thread overview] Message-ID: <KU1P153MB016637CAEAD346F0AA8E3801BFAD0@KU1P153MB0166.APCP153.PROD.OUTLOOK.COM> (raw) 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 <decui at microsoft.com> --- 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
WARNING: multiple messages have this Message-ID (diff)
From: Dexuan Cui <decui@microsoft.com> To: "lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>, "bhelgaas@google.com" <bhelgaas@google.com>, "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org> Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>, Stephen Hemminger <sthemmin@microsoft.com>, "jackm@mellanox.com" <jackm@mellanox.com>, Haiyang Zhang <haiyangz@microsoft.com>, "driverdev-devel@linuxdriverproject.org" <driverdev-devel@linuxdriverproject.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Michael Kelley <mikelley@microsoft.com>, Sasha Levin <Alexander.Levin@microsoft.com>, "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>, "olaf@aepfle.de" <olaf@aepfle.de>, "apw@canonical.com" <apw@canonical.com>, vkuznets <vkuznets@redhat.com>, "jasowang@redhat.com" <jasowang@redhat.com> Subject: [PATCH v2] PCI: PM: Move to D0 before calling pci_legacy_resume_early() Date: Wed, 14 Aug 2019 01:06:55 +0000 [thread overview] Message-ID: <KU1P153MB016637CAEAD346F0AA8E3801BFAD0@KU1P153MB0166.APCP153.PROD.OUTLOOK.COM> (raw) Message-ID: <20190814010655.OyGp3I6mJof0JByM87AQs18D1SXO3reK_JyI3XL1l4c@z> (raw) 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 <decui@microsoft.com> --- 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 _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
next reply other threads:[~2019-08-14 1:06 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-14 1:06 Dexuan Cui [this message] 2019-08-14 1:06 ` [PATCH v2] PCI: PM: Move to D0 before calling pci_legacy_resume_early() Dexuan Cui 2019-09-03 0:34 ` Dexuan Cui 2019-09-25 22:25 ` Dexuan Cui 2019-10-07 13:24 ` Bjorn Helgaas 2019-10-07 18:57 ` Dexuan Cui 2019-10-08 17:32 ` Rafael J. Wysocki 2019-10-08 19:56 ` Bjorn Helgaas 2019-10-09 0:16 ` Dexuan Cui 2019-10-10 16:45 ` Rafael J. Wysocki
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