This is a note to let you know that I've just added the patch titled
PCI: Configure ASPM when enabling device
to the 3.16-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-configure-aspm-when-enabling-device.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1f6ae47ecff7f23da73417e068018b311f3b5583 Mon Sep 17 00:00:00 2001
From: Vidya Sagar <sagar.tv@xxxxxxxxx>
Date: Wed, 16 Jul 2014 15:33:42 +0530
Subject: PCI: Configure ASPM when enabling device
From: Vidya Sagar <sagar.tv@xxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Vidya Sagar <sagar.tv@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/pci.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -839,12 +839,6 @@ int pci_set_power_state(struct pci_dev *
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;
}
@@ -1195,12 +1189,18 @@ int __weak pcibios_enable_device(struct
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;
Patches currently in stable-queue which might be from sagar.tv@xxxxxxxxx are
queue-3.16/pci-configure-aspm-when-enabling-device.patch
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