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authorDexuan Cui <decui@microsoft.com>2019-08-14 04:06:55 +0300
committerBjorn Helgaas <bhelgaas@google.com>2019-11-21 02:32:25 +0300
commitf2c33ccacb2d4bbeae2a255a7ca0cbfd03017b7c (patch)
treefa6fbc99def14f16a81b76d61e242afb5618d2cf /Documentation
parent7d194c2100ad2a6dded545887d02754948ca5241 (diff)
downloadlinux-f2c33ccacb2d4bbeae2a255a7ca0cbfd03017b7c.tar.xz
PCI/PM: Always return devices to D0 when thawing
pci_pm_thaw_noirq() is supposed to return the device to D0 and restore its configuration registers, but previously it only did that for devices whose drivers implemented the new power management ops. Hibernation, e.g., via "echo disk > /sys/power/state", involves freezing devices, creating a hibernation image, thawing devices, writing the image, and powering off. The fact that thawing did not return devices with legacy power management to D0 caused errors, e.g., in this path: pci_pm_thaw_noirq if (pci_has_legacy_pm_support(pci_dev)) # true for Mellanox VF driver return pci_legacy_resume_early(dev) # ... legacy PM skips the rest pci_set_power_state(pci_dev, PCI_D0) pci_restore_state(pci_dev) pci_pm_thaw if (pci_has_legacy_pm_support(pci_dev)) pci_legacy_resume drv->resume mlx4_resume ... pci_enable_msix_range ... if (dev->current_state != PCI_D0) # <--- return -EINVAL; which caused these warnings: 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 Return devices to D0 and restore config registers for all devices, not just those whose drivers support new power management. [bhelgaas: also call pci_restore_state() before pci_legacy_resume_early(), update comment, add stable tag, commit log] Link: https://lore.kernel.org/r/KU1P153MB016637CAEAD346F0AA8E3801BFAD0@KU1P153MB0166.APCP153.PROD.OUTLOOK.COM Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: stable@vger.kernel.org # v4.13+
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