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Date: Fri, 18 Jun 2010 10:15:24 -0700 From: Jesse Barnes <jbarnes@...tuousgeek.org> To: Matthew Garrett <mjg@...hat.com> Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] pci: Don't enable aspm before drivers have had a chance to veto it On Wed, 9 Jun 2010 16:05:07 -0400 Matthew Garrett <mjg@...hat.com> wrote: > 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. > > Signed-off-by: Matthew Garrett <mjg@...hat.com> > --- > > Cleaned up slightly to remove the hacky aspm_policy changing. > > drivers/pci/pcie/aspm.c | 16 ++++++++++++++-- > 1 files changed, 14 insertions(+), 2 deletions(-) > > 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: Applied to linux-next, thanks. -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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