Messages in this thread | | | From | Roman Fietze <> | Subject | ASPM, devices with mixed PCIe/PCI functions | Date | Wed, 15 Feb 2012 12:48:34 +0100 |
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Hello,
I'm referring to commit ddc9753fcddfe5f.
On our system we use a PCIe-Local-Bridge, the PEX8311, which internally is a quick and dirty design glued together using a PEX8111 and a PEX9056. I'm now just talking about the PEX8111, which is a PCIe to PCI-X bridge.
The function pcie_aspm_sanity_check() in drivers/pci/pcie/aspm.c disables ASPM for this bridge, because the child (PEX9056) is not PCIe, hereby disabling power savings on the upstream PCIe link.
Is this a flaw? What is the reason for this? Could please someone with more PCI(e) knowledge enlighten me?
I'm of course willing to deliver a patch to fix this (IMHO) problem, but this only makes sense if I'm not totally wrong in my assumption, that ASPM should be enabled on such devices (besides the fact, that the PEX8111 does not have PCI_EXP_DEVCAP_RBER set).
Roman
-- Roman Fietze Telemotive AG Buero Muehlhausen Breitwiesen 73347 Muehlhausen Tel.: +49(0)7335/18493-45 http://www.telemotive.de
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