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path: root/drivers/pci/controller/pci-aardvark.c
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Diffstat (limited to 'drivers/pci/controller/pci-aardvark.c')
-rw-r--r--drivers/pci/controller/pci-aardvark.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 669663fb982e..ff45052cf48d 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -998,8 +998,12 @@ static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
return false;
/*
- * If the link goes down after we check for link-up, nothing bad
- * happens but the config access times out.
+ * If the link goes down after we check for link-up, we have a problem:
+ * if a PIO request is executed while link-down, the whole controller
+ * gets stuck in a non-functional state, and even after link comes up
+ * again, PIO requests won't work anymore, and a reset of the whole PCIe
+ * controller is needed. Therefore we need to prevent sending PIO
+ * requests while the link is down.
*/
if (!pci_is_root_bus(bus) && !advk_pcie_link_up(pcie))
return false;