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Subject[PATCH v3] PCI: enable ASPM configuration in PCIE POWERSAVE mode
Date
From: Vidya Sagar <sagar.tv@gmail.com>

Commit 1a680b7c3258 ("PCI: PCIe links may not get configured for ASPM
under POWERSAVE mode") moved pcie_aspm_powersave_config_link() out of
pci_raw_set_power_state() to pci_set_power_state() which would enable
ASPM. But, with Commit db288c9c5f9d ("PCI / PM: restore the original
behavior of pci_set_power_state()"), which re-introduced the following check
./drivers/pci/pci.c: pci_set_power_state()

+ /* Check if we're already there */
+ if (dev->current_state == state)
+ return 0;

in pci_set_power_state(), call to pcie_aspm_powersave_config_link() is never
made leaving ASPM broken.
Fix it by configuring links for ASPM in do_pci_enable_device() instead of
pci_set_power_state()

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Vidya Sagar <sagar.tv@gmail.com>
---
v3:
* Modified commit message
removed single quotes around commit messages
added Suggested-by line

v2:
* Calling ASPM config code is moved from pci_set_power_state() to
* do_pci_enable_device()

drivers/pci/pci.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1c8592b..81d49d3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -839,12 +839,6 @@ 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;
}
@@ -1195,12 +1189,18 @@ int __weak pcibios_enable_device(struct pci_dev *dev, int bars)
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;
--
1.8.1.5


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