On Tue, Sep 18, 2012 at 7:07 PM, Dave Airlie <airlied@xxxxxxxxxx> wrote:
> If the driver takes care of state saving, don't touch any registers on it.
>
> Optimus (dual-gpu) laptops seem to have their own form of D3cold, but
> unfortunately enter it on normal D3 transitions via the ACPI callback.
>
> So when we use runtime PM to transition to D3, the card disappears off
> the PCI bus, however we then try to access registers on it in the
> runtime suspend finish, which really doesn't work.
>
> This patch check is the pci state is saved and doesn't attempt to hit
> any registers after that point if it is.
>
> (Looks okay to Rafael)
>
> Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
I applied this to my pci/misc branch as v3.8 material.
Let me know if this should be v3.7 material or if it needs to be
backported to -stable (and how far if so).
> ---
> drivers/pci/pci-driver.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 5270f1a..214a40b 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -1057,10 +1057,11 @@ static int pci_pm_runtime_suspend(struct device *dev)
> return 0;
> }
>
> - if (!pci_dev->state_saved)
> + if (!pci_dev->state_saved) {
> pci_save_state(pci_dev);
>
> - pci_finish_runtime_suspend(pci_dev);
> + pci_finish_runtime_suspend(pci_dev);
> + }
>
> return 0;
> }
> --
> 1.7.12
>
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