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linux-next/include/linux/pci-aspm.h
Naga Chumbalkar 1a680b7c32 PCI: PCIe links may not get configured for ASPM under POWERSAVE mode
v3 -> v2: Moved ASPM enabling logic to pci_set_power_state()
v2 -> v1: Preserved the logic in pci_raw_set_power_state()
	: Added ASPM enabling logic after scanning Root Bridge
	: http://marc.info/?l=linux-pci&m=130046996216391&w=2
v1	: http://marc.info/?l=linux-pci&m=130013164703283&w=2

The assumption made in commit 41cd766b06
(PCI: Don't enable aspm before drivers have had a chance to veto it) that
pci_enable_device() will result in re-configuring ASPM when aspm_policy is
POWERSAVE is no longer valid.  This is due to commit
97c145f7c8 (PCI: read current power state
at enable time) which resets dev->current_state to D0. Due to this the
call to pcie_aspm_pm_state_change() is never made. Note the equality check
(below) that returns early:
./drivers/pci/pci.c: pci_raw_set_pci_power_state()
546         /* Check if we're already there */
547         if (dev->current_state == state)
548                 return 0;

Therefore OSPM never configures the PCIe links for ASPM to turn them "on".

Fix it by configuring ASPM from the pci_enable_device() code path. This
also allows a driver such as the e1000e networking driver a chance to
disable ASPM (L0s, L1), if need be, prior to enabling the device. A
driver may perform this action if the device is known to mis-behave
wrt ASPM.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-03-21 09:40:43 -07:00

69 lines
1.7 KiB
C

/*
* aspm.h
*
* PCI Express ASPM defines and function prototypes
*
* Copyright (C) 2007 Intel Corp.
* Zhang Yanmin (yanmin.zhang@intel.com)
* Shaohua Li (shaohua.li@intel.com)
*
* For more information, please consult the following manuals (look at
* http://www.pcisig.com/ for how to get them):
*
* PCI Express Specification
*/
#ifndef LINUX_ASPM_H
#define LINUX_ASPM_H
#include <linux/pci.h>
#define PCIE_LINK_STATE_L0S 1
#define PCIE_LINK_STATE_L1 2
#define PCIE_LINK_STATE_CLKPM 4
#ifdef CONFIG_PCIEASPM
extern void pcie_aspm_init_link_state(struct pci_dev *pdev);
extern void pcie_aspm_exit_link_state(struct pci_dev *pdev);
extern void pcie_aspm_pm_state_change(struct pci_dev *pdev);
extern void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
extern void pci_disable_link_state(struct pci_dev *pdev, int state);
extern void pcie_clear_aspm(void);
extern void pcie_no_aspm(void);
#else
static inline void pcie_aspm_init_link_state(struct pci_dev *pdev)
{
}
static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev)
{
}
static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev)
{
}
static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
{
}
static inline void pci_disable_link_state(struct pci_dev *pdev, int state)
{
}
static inline void pcie_clear_aspm(void)
{
}
static inline void pcie_no_aspm(void)
{
}
#endif
#ifdef CONFIG_PCIEASPM_DEBUG /* this depends on CONFIG_PCIEASPM */
extern void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
extern void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
#else
static inline void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
{
}
static inline void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
{
}
#endif
#endif /* LINUX_ASPM_H */