diff options
| author | Naga Chumbalkar <nagananda.chumbalkar@hp.com> | 2011-03-21 03:29:08 +0000 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2011-03-21 09:40:43 -0700 |
| commit | 1a680b7c325882188865f05b9a88d32f75f26495 (patch) | |
| tree | eb3844655f9ff01630157e4b2c039759970b1a94 /drivers/pci | |
| parent | 8b8bae901ce23addbdcdb54fa1696fb2d049feb5 (diff) | |
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 41cd766b065970ff6f6c89dd1cf55fa706c84a3d
(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POWERSAVE is no longer valid.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
97c145f7c87453cec90e91238fba5fe2c1561b32 (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>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/pci.c | 6 | ||||
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 22 |
2 files changed, 28 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b714d787bdd..2472e7177b4 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -740,6 +740,12 @@ 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; } diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index bbdb4fd85b9..e61b82e611c 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -708,6 +708,28 @@ void pcie_aspm_pm_state_change(struct pci_dev *pdev) up_read(&pci_bus_sem); } +void pcie_aspm_powersave_config_link(struct pci_dev *pdev) +{ + struct pcie_link_state *link = pdev->link_state; + + if (aspm_disabled || !pci_is_pcie(pdev) || !link) + return; + + if (aspm_policy != POLICY_POWERSAVE) + return; + + if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) && + (pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)) + return; + + down_read(&pci_bus_sem); + mutex_lock(&aspm_lock); + pcie_config_aspm_path(link); + pcie_set_clkpm(link, policy_to_clkpm_state(link)); + mutex_unlock(&aspm_lock); + up_read(&pci_bus_sem); +} + /* * pci_disable_link_state - disable pci device's link state, so the link will * never enter specific states |