linux-kernel - [ 30/64] PCI/PM: Disable runtime PM of PCIe ports

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Date:	Wed, 10 Apr 2013 15:46:27 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: [ 30/64] PCI/PM: Disable runtime PM of PCIe ports

3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>

commit de7d5f729c72638f41d7c17487bccb1c570ff144 upstream.

The runtime PM of PCIe ports turns out to be quite fragile, as in
some cases things work while in some other cases they don't and we
don't seem to have a good way to determine whether or not they are
going to work in advance.

For this reason, avoid enabling runtime PM for PCIe ports by
keeping their runtime PM reference counters always above 0 for the
time being.

When a PCIe port is suspended, it can no longer report events like
hotplug, so hotplug below the port may not work, as in the bug
report below.

[bhelgaas: changelog, stable]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=53811
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/pci/pcie/portdrv_pci.c |   13 -------------
 1 file changed, 13 deletions(-)

--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -185,14 +185,6 @@ static const struct dev_pm_ops pcie_port
 #endif /* !PM */

 /*
- * PCIe port runtime suspend is broken for some chipsets, so use a
- * black list to disable runtime PM for these chipsets.
- */
-static const struct pci_device_id port_runtime_pm_black_list[] = {
-	{ /* end: all zeroes */ }
-};
-
-/*
  * pcie_portdrv_probe - Probe PCI-Express port devices
  * @dev: PCI-Express port device being probed
  *
@@ -225,16 +217,11 @@ static int pcie_portdrv_probe(struct pci
 	 * it by default.
 	 */
 	dev->d3cold_allowed = false;
-	if (!pci_match_id(port_runtime_pm_black_list, dev))
-		pm_runtime_put_noidle(&dev->dev);
-
 	return 0;
 }

 static void pcie_portdrv_remove(struct pci_dev *dev)
 {
-	if (!pci_match_id(port_runtime_pm_black_list, dev))
-		pm_runtime_get_noresume(&dev->dev);
 	pcie_port_device_remove(dev);
 	pci_disable_device(dev);
 }

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