[PATCH V5 2/4] PCI/ASPM: add init hook to device_add

From: Sinan Kaya
Date: Sat Mar 25 2017 - 17:39:14 EST


For bridges, have pcie_aspm_init_link_state() allocate a link_state,
regardless of whether it currently has any children.

pcie_aspm_init_link_state(): Called for bridges (upstream end of
link) after all children have been enumerated. No longer needs to
check aspm_support_enabled or pdev->has_secondary_link or the VIA
quirk: pci_aspm_init() already checked that stuff, so we only need
to check pdev->link_state here.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=194895
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 41 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 74fd7c5..f5b1fa0 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -834,6 +834,23 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
*/
int pci_aspm_init(struct pci_dev *pdev)
{
+ struct pcie_link_state *link;
+
+ if (!aspm_support_enabled)
+ return 0;
+
+ /* VIA has a strange chipset, root port is under a bridge */
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->bus->self)
+ return 0;
+
+ if (!pdev->has_secondary_link)
+ return 0;
+
+ link = alloc_pcie_link_state(pdev);
+ if (!link)
+ return -ENOMEM;
+
return 0;
}

@@ -847,33 +864,16 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
struct pcie_link_state *link;
int blacklist = !!pcie_aspm_sanity_check(pdev);

- if (!aspm_support_enabled)
- return;
-
- if (pdev->link_state)
- return;
-
- /*
- * We allocate pcie_link_state for the component on the upstream
- * end of a Link, so there's nothing to do unless this device has a
- * Link on its secondary side.
- */
- if (!pdev->has_secondary_link)
- return;
-
- /* VIA has a strange chipset, root port is under a bridge */
- if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
- pdev->bus->self)
+ if (!pdev->link_state)
return;

+ link = pdev->link_state;
down_read(&pci_bus_sem);
if (list_empty(&pdev->subordinate->devices))
goto out;

mutex_lock(&aspm_lock);
- link = alloc_pcie_link_state(pdev);
- if (!link)
- goto unlock;
+
/*
* Setup initial ASPM state. Note that we need to configure
* upstream links also because capable state of them can be
@@ -898,7 +898,6 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
pcie_set_clkpm(link, policy_to_clkpm_state(link));
}

-unlock:
mutex_unlock(&aspm_lock);
out:
up_read(&pci_bus_sem);
--
1.9.1