From 4b4f9f172af402d4d4c01cc63d77d115af637d32 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marek=20Beh=C3=BAn?= Date: Wed, 4 May 2022 18:57:55 +0200 Subject: [PATCH] PCI: aardvark: Update comment about link going down after link-up MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 92f4ffecc4170ce29e67a1f8d51c168c3de95fb2 upstream. Update the comment about what happens when link goes down after we have checked for link-up. If a PIO request is done while link-down, we have a serious problem. Link: https://lore.kernel.org/r/20220110015018.26359-23-kabel@kernel.org Signed-off-by: Marek Behún Signed-off-by: Lorenzo Pieralisi Signed-off-by: Marek Behún Signed-off-by: Greg Kroah-Hartman --- drivers/pci/controller/pci-aardvark.c | 8 ++++++-- 1 file 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;