From: Kai-Heng Feng kai.heng.feng@canonical.com
[ Upstream commit 66ff14e59e8a30690755b08bc3042359703fb07a ]
7d715a6c1ae5 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/pcie/aspm.c | 10 ---------- 1 file changed, 10 deletions(-)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index c6a012b5ba390..966b6947e5656 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -388,16 +388,6 @@ 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) {