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

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2068174
Upstream Status: 92f4ffecc4170ce29e67a1f8d51c168c3de95fb2

commit 92f4ffecc4170ce29e67a1f8d51c168c3de95fb2
Author: Marek Behún <kabel@kernel.org>
Date:   Mon Jan 10 02:50:17 2022 +0100

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

    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>

Signed-off-by: Myron Stowe <mstowe@redhat.com>
This commit is contained in:
Myron Stowe 2022-05-06 10:03:12 -06:00
parent 51ea6b44cd
commit c4361232b2
1 changed files with 6 additions and 2 deletions
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8
drivers/pci/controller/pci-aardvark.c
View File

@ -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;