From 41cd766b065970ff6f6c89dd1cf55fa706c84a3d Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Wed, 9 Jun 2010 16:05:07 -0400 Subject: 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 --- drivers/pci/pcie/aspm.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index be53d98fa384..71222814c1ec 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: -- cgit v1.2.1