This is a note to let you know that I've just added the patch titled
PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-pm-force-devices-to-d0-in-pci_pm_thaw_noirq.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5839ee7389e893a31e4e3c9cf17b50d14103c902 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Date: Fri, 15 Dec 2017 03:07:18 +0100
Subject: PCI / PM: Force devices to D0 in pci_pm_thaw_noirq()
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
commit 5839ee7389e893a31e4e3c9cf17b50d14103c902 upstream.
It is incorrect to call pci_restore_state() for devices in low-power
states (D1-D3), as that involves the restoration of MSI setup which
requires MMIO to be operational and that is only the case in D0.
However, pci_pm_thaw_noirq() may do that if the driver's "freeze"
callbacks put the device into a low-power state, so fix it by making
it force devices into D0 via pci_set_power_state() instead of trying
to "update" their power state which is pointless.
Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation)
Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reported-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
Tested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/pci-driver.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -944,7 +944,12 @@ static int pci_pm_thaw_noirq(struct devi
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_resume_early(dev);
- pci_update_current_state(pci_dev, PCI_D0);
+ /*
+ * 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);
pci_restore_state(pci_dev);
if (drv && drv->pm && drv->pm->thaw_noirq)
Patches currently in stable-queue which might be from rafael.j.wysocki@xxxxxxxxx are
queue-4.4/pci-pm-force-devices-to-d0-in-pci_pm_thaw_noirq.patch
queue-4.4/acpi-apei-erst-fix-missing-error-handling-in-erst_reader.patch