[v4,1/2] PCI / PM: Add needs_resume flag to avoid suspend complete optimization

Some drivers - like i915 - may not support the system suspend direct
complete optimization due to differences in their runtime and system
suspend sequence. Add a flag that when set resumes the device before
calling the driver's system suspend handlers which effectively disables
the optimization.

Needed by the next patch fixing suspend/resume on i915.

Suggested by Rafael.

v2-v3:
- unchanged

v4:
- Move the flag to dev_flags instead of using a bit field. (Rafael)

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> (v3)
---
 drivers/pci/pci.c   | 3 ++-
 include/linux/pci.h | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

On Tuesday, May 02, 2017 03:04:08 PM Imre Deak wrote:
> Some drivers - like i915 - may not support the system suspend direct
> complete optimization due to differences in their runtime and system
> suspend sequence. Add a flag that when set resumes the device before
> calling the driver's system suspend handlers which effectively disables
> the optimization.
> 
> Needed by the next patch fixing suspend/resume on i915.
> 
> Suggested by Rafael.
> 
> v2-v3:
> - unchanged
> 
> v4:
> - Move the flag to dev_flags instead of using a bit field. (Rafael)

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

And yes, the PCI device PM flags need to be cleaned up.  I'll take care of this
later unless somebody else steps up.

> 
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> Cc: stable@vger.kernel.org
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> (v3)
> ---
>  drivers/pci/pci.c   | 3 ++-
>  include/linux/pci.h | 5 +++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7904d02..a4ef755 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2141,7 +2141,8 @@ bool pci_dev_keep_suspended(struct pci_dev *pci_dev)
>  
>  	if (!pm_runtime_suspended(dev)
>  	    || pci_target_state(pci_dev) != pci_dev->current_state
> -	    || platform_pci_need_resume(pci_dev))
> +	    || platform_pci_need_resume(pci_dev)
> +	    || (pci_dev->dev_flags & PCI_DEV_FLAGS_NEEDS_RESUME))
>  		return false;
>  
>  	/*
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 5948cfd..8acb560 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -178,6 +178,11 @@ enum pci_dev_flags {
>  	PCI_DEV_FLAGS_NO_PM_RESET = (__force pci_dev_flags_t) (1 << 7),
>  	/* Get VPD from function 0 VPD */
>  	PCI_DEV_FLAGS_VPD_REF_F0 = (__force pci_dev_flags_t) (1 << 8),
> +	/*
> +	 * Resume before calling the driver's system suspend hooks, disabling
> +	 * the direct_complete optimization.
> +	 */
> +	PCI_DEV_FLAGS_NEEDS_RESUME = (__force pci_dev_flags_t) (1 << 9),
>  };
>  
>  enum pci_irq_reroute_variant {
>