linux-kernel - [PATCH v1] PCI: enable ASPM configuration in PCIE POWERSAVE mode

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Date:	Tue, 1 Jul 2014 12:46:18 +0530
From:	Vidya Sagar <vidyas@...dia.com>
To:	<bhelgaas@...gle.com>, <rjw@...k.pl>,
	<nagananda.chumbalkar@...com>, <thierry.reding@...il.com>,
	<swarren@...dia.com>, <kthota@...dia.com>,
	<linux-pci@...r.kernel.org>
CC:	<linux-kernel@...r.kernel.org>, Vidya Sagar <vidyas@...dia.com>
Subject: [PATCH v1] PCI: enable ASPM configuration in PCIE POWERSAVE mode

commit 1a680b7c 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 db288c9c, 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 not returning from when the above condition is true, rather, jump to
ASPM configuration code and exit from there eventually.

Signed-off-by: Vidya Sagar <vidyas@...dia.com>
---
 drivers/pci/pci.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1c8592b..ded24c4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -804,7 +804,7 @@ EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
  */
 int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
-	int error;
+	int error = 0;
 
 	/* bound the state we're entering */
 	if (state > PCI_D3cold)
@@ -821,7 +821,7 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 
 	/* Check if we're already there */
 	if (dev->current_state == state)
-		return 0;
+		goto config_aspm;
 
 	__pci_start_power_transition(dev, state);
 
@@ -839,6 +839,8 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 
 	if (!__pci_complete_power_transition(dev, state))
 		error = 0;
+
+config_aspm:
 	/*
 	 * When aspm_policy is "powersave" this call ensures
 	 * that ASPM is configured.
-- 
1.8.1.5

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