From: Matthew Garrett Date: Wed, 9 Jun 2010 20:05:07 +0000 (-0400) Subject: PCI: Don't enable aspm before drivers have had a chance to veto it X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fjbarnes%2Fpci-2.6.git;a=commitdiff_plain;h=8f0b08c29f1df91315e48adce04462eb23671099 PCI: Don't enable aspm before drivers have had a chance to veto it The aspm code will currently set the configured aspm policy before drivers have had an opportunity to indicate that their hardware doesn't support it. Unfortunately, putting some hardware in L0 or L1 can result in the hardware no longer responding to any requests, even after aspm is disabled. It makes more sense to leave aspm policy at the BIOS defaults at initial setup time, reconfiguring it after pci_enable_device() is called. This allows the driver to blacklist individual devices beforehand. Reviewed-by: Kenji Kaneshige Signed-off-by: Matthew Garrett Signed-off-by: Jesse Barnes --- diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index be53d98..7122281 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -588,11 +588,23 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * update through pcie_aspm_cap_init(). */ pcie_aspm_cap_init(link, blacklist); - pcie_config_aspm_path(link); /* Setup initial Clock PM state */ pcie_clkpm_cap_init(link, blacklist); - pcie_set_clkpm(link, policy_to_clkpm_state(link)); + + /* + * At this stage drivers haven't had an opportunity to change the + * link policy setting. Enabling ASPM on broken hardware can cripple + * it even before the driver has had a chance to disable ASPM, so + * default to a safe level right now. If we're enabling ASPM beyond + * the BIOS's expectation, we'll do so once pci_enable_device() is + * called. + */ + if (aspm_policy != POLICY_POWERSAVE) { + pcie_config_aspm_path(link); + pcie_set_clkpm(link, policy_to_clkpm_state(link)); + } + unlock: mutex_unlock(&aspm_lock); out: