lkml.org 
[lkml]   [2010]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] pci: Don't enable aspm before drivers have had a chance to veto it
    Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>


    (2010/06/10 5:05), Matthew Garrett 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@redhat.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:




    \
     
     \ /
      Last update: 2010-06-10 04:09    [W:0.024 / U:1.680 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site