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PCI: Don't clear ASPM bits when the FADT declares it's unsupported

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Communications with a hardware vendor confirm that the expected behaviour
on systems that set the FADT ASPM disable bit but which still grant full
PCIe control is for the OS to leave any BIOS configuration intact and
refuse to touch the ASPM bits.  This mimics the behaviour of Windows.

Signed-off-by: Matthew Garrett <mjg59@coreos.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Matthew Garrett
2015-04-07 11:07:00 -07:00
committed by Bjorn Helgaas
parent 37a9c502c0
commit 387d37577f
3 changed files with 8 additions and 33 deletions
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18
drivers/pci/pcie/aspm.c
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@@ -782,24 +782,6 @@ void pci_disable_link_state(struct pci_dev *pdev, int state)
}
EXPORT_SYMBOL(pci_disable_link_state);
void pcie_clear_aspm(struct pci_bus *bus)
{
struct pci_dev *child;
if (aspm_force)
return;
/*
* Clear any ASPM setup that the firmware has carried out on this bus
*/
list_for_each_entry(child, &bus->devices, bus_list) {
__pci_disable_link_state(child, PCIE_LINK_STATE_L0S |
PCIE_LINK_STATE_L1 |
PCIE_LINK_STATE_CLKPM,
false, true);
}
}
static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp)
{
int i;