PCI: sysfs: Resume to D0 on function reset

This change “PCI: sysfs: Resume to D0 on function reset” in Linux kernel is authored by Lukas Wunner <lukas [at] wunner.de> on Thu Jul 19 17:27:58 2018 -0500.

PCI: sysfs: Resume to D0 on function reset

When performing a function reset via sysfs, the device's config space is
accessed in places such as pcie_flr() and its MMIO space is accessed e.g.
in reset_ivb_igd(), so ensure accessibility by resuming the device to D0.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 82c3fbf.

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/pci/pci-sysfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 0c4653c..a3df6b5 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1449,7 +1449,9 @@ static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
 	if (val != 1)
 		return -EINVAL;
+	pm_runtime_get_sync(dev);
 	result = pci_reset_function(pdev);
+	pm_runtime_put(dev);
 	if (result < 0)
 		return result;

The commit for this change in Linux stable tree is 82c3fbf (patch).

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