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PCI: aardvark: Update comment about link going down after link-up

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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 <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
This commit is contained in:
Marek Behún 2022-01-10 02:50:17 +01:00 committed by Lorenzo Pieralisi
parent 0c36ab437e
commit 92f4ffecc4
1 changed files with 6 additions and 2 deletions
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8
drivers/pci/controller/pci-aardvark.c
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@ -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;