PCI/PM: Add needs_resume flag to avoid suspend complete optimization

commit 4d071c3238987325b9e50e33051a40d1cce311cc upstream.

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 a future patch fixing suspend/resume on i915.

Suggested by Rafael.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org
(rebased on v4.8, added kernel version to commit message stable tag)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 579c494..e7d4048 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2142,7 +2142,8 @@ 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 a38772a..1b71179 100644 (file)
--- 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 << 11),
 };
 
 enum pci_irq_reroute_variant {