diff mbox

[3.13.y.z,extended,stable] Patch "PCI: Configure ASPM when enabling device" has been added to staging queue

Message ID 1410818858-4499-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Sept. 15, 2014, 10:07 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    PCI: Configure ASPM when enabling device

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From 18b6d98fc24921af2b83c8f80275cf3a267f312c Mon Sep 17 00:00:00 2001
From: Vidya Sagar <sagar.tv@gmail.com>
Date: Wed, 16 Jul 2014 15:33:42 +0530
Subject: PCI: Configure ASPM when enabling device

commit 1f6ae47ecff7f23da73417e068018b311f3b5583 upstream.

We can't do ASPM configuration at enumeration-time because enabling it
makes some defective hardware unresponsive, even if ASPM is disabled later
(see 41cd766b0659 ("PCI: Don't enable aspm before drivers have had a chance
to veto it").  Therefore, we have to do it after a driver claims the
device.

We previously configured ASPM in pci_set_power_state(), but that's not a
very good place because it's not really related to setting the PCI device
power state, and doing it there means:

  - We incorrectly skipped ASPM config when setting a device that's
    already in D0 to D0.

  - We unnecessarily configured ASPM when setting a device to a low-power
    state (the ASPM feature only applies when the device is in D0).

  - We unnecessarily configured ASPM when called from a .resume() method
    (ASPM configuration needs to be restored during resume, but
    pci_restore_pcie_state() should already do this).

Move ASPM configuration from pci_set_power_state() to
do_pci_enable_device() so we do it when a driver enables a device.

[bhelgaas: changelog]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=79621
Fixes: db288c9c5f9d ("PCI / PM: restore the original behavior of pci_set_power_state()")
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Vidya Sagar <sagar.tv@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/pci/pci.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--
1.9.1
diff mbox

Patch

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1a8a4fd..49ca284 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -782,12 +782,6 @@  int pci_set_power_state(struct pci_dev *dev, pci_power_t state)

 	if (!__pci_complete_power_transition(dev, state))
 		error = 0;
-	/*
-	 * When aspm_policy is "powersave" this call ensures
-	 * that ASPM is configured.
-	 */
-	if (!error && dev->bus->self)
-		pcie_aspm_powersave_config_link(dev->bus->self);

 	return error;
 }
@@ -1120,12 +1114,18 @@  EXPORT_SYMBOL_GPL(pci_load_and_free_saved_state);
 static int do_pci_enable_device(struct pci_dev *dev, int bars)
 {
 	int err;
+	struct pci_dev *bridge;
 	u16 cmd;
 	u8 pin;

 	err = pci_set_power_state(dev, PCI_D0);
 	if (err < 0 && err != -EIO)
 		return err;
+
+	bridge = pci_upstream_bridge(dev);
+	if (bridge)
+		pcie_aspm_powersave_config_link(bridge);
+
 	err = pcibios_enable_device(dev, bars);
 	if (err < 0)
 		return err;