[+cc Matthew, Rafael]
On Mon, Jul 14, 2014 at 12:04 AM, Vidya Sagar <sagar.tv@xxxxxxxxx> wrote:
> From: Vidya Sagar <sagar.tv@xxxxxxxxx>
>
> 'commit 1a680b7c3258 ("PCI: PCIe links may not get configured for ASPM
> under POWERSAVE mode")' moved pcie_aspm_powersave_config_link() out of
> pci_raw_set_power_state() to pci_set_power_state() which would enable
> ASPM. But, with 'commit db288c9c5f9d ("PCI / PM: restore the original
> behavior of pci_set_power_state()")', which re-introduced the following check
> ./drivers/pci/pci.c: pci_set_power_state()
> + /* Check if we're already there */
> + if (dev->current_state == state)
> + return 0;
> in pci_set_power_state(), call to pcie_aspm_powersave_config_link() is never
> made leaving ASPM broken.
> Fix it by not returning from when the above condition is true, rather, jump to
> ASPM configuration code and exit from there eventually.
>
> Signed-off-by: Vidya Sagar <sagar.tv@xxxxxxxxx>
I'm OK with the patch (obviously, since I wrote it), but you neglected
to copy Matthew and Rafael. And you forgot to rewrite the changelog.
I'll take care of the changelog, but I would like to see something
from Matthew and Rafael, since this is a significant change in how we
configure ASPM.
Matthew, Rafael, my observation was: "But I wonder if we can untangle
ASPM from pci_set_power_state(). I don't think they're really
related. There are a zillion .suspend() and .resume() methods that
call pci_set_power_state(). I doubt that we need to do ASPM
configuration during suspend, and I'm dubious about resume, too."
So the new patch moves the pcie_aspm_powersave_config_link() call out
of pci_set_power_state() and into do_pci_enable_device().
Bjorn
> ---
> v2:
> * Calling ASPM config code is moved from pci_set_power_state() to
> * do_pci_enable_device()
>
> drivers/pci/pci.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 1c8592b..81d49d3 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -839,12 +839,6 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
>
> if (!__pci_complete_power_transition(dev, state))
> error = 0;
> - /*
> - * When aspm_policy is "powersave" this call ensures
> - * that ASPM is configured.
> - */
> - if (!error && dev->bus->self)
> - pcie_aspm_powersave_config_link(dev->bus->self);
>
> return error;
> }
> @@ -1195,12 +1189,18 @@ int __weak pcibios_enable_device(struct pci_dev *dev, int bars)
> static int do_pci_enable_device(struct pci_dev *dev, int bars)
> {
> int err;
> + struct pci_dev *bridge;
> u16 cmd;
> u8 pin;
>
> err = pci_set_power_state(dev, PCI_D0);
> if (err < 0 && err != -EIO)
> return err;
> +
> + bridge = pci_upstream_bridge(dev);
> + if (bridge)
> + pcie_aspm_powersave_config_link(bridge);
> +
> err = pcibios_enable_device(dev, bars);
> if (err < 0)
> return err;
> --
> 1.8.1.5
>
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