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PCI/ASPM: Allow ASPM on links to PCIe-to-PCI/PCI-X Bridges 

7d715a6c1a ("PCI: add PCI Express ASPM support") added the ability for
Linux to enable ASPM, but for some undocumented reason, it didn't enable
ASPM on links where the downstream component is a PCIe-to-PCI/PCI-X Bridge.

Remove this exclusion so we can enable ASPM on these links.

The Dell OptiPlex 7080 mentioned in the bugzilla has a TI XIO2001
PCIe-to-PCI Bridge.  Enabling ASPM on the link leading to it allows the
Intel SoC to enter deeper Package C-states, which is a significant power
savings.

[bhelgaas: commit log]
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=207571
Link: https://lore.kernel.org/r/20200505173423.26968-1-kai.heng.feng@canonical.com
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Kai-Heng Feng 2020-05-06 01:34:21 +08:00 committed by Bjorn Helgaas
parent 8f3d9f3542
commit 66ff14e59e
1 changed files with 0 additions and 10 deletions
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10
drivers/pci/pcie/aspm.c
View File

@ -628,16 +628,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
/* Setup initial capable state. Will be updated later */
link->aspm_capable = link->aspm_support;
/*
* If the downstream component has pci bridge function, don't
* do ASPM for now.
*/
list_for_each_entry(child, &linkbus->devices, bus_list) {
if (pci_pcie_type(child) == PCI_EXP_TYPE_PCI_BRIDGE) {
link->aspm_disable = ASPM_STATE_ALL;
break;
}
}
/* Get and check endpoint acceptable latencies */
list_for_each_entry(child, &linkbus->devices, bus_list) {