2022-01-10 09:12:45 +08:00
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From bafda858364003a70b9cda84282f9761587f8033 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
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Date: Mon, 10 Jan 2022 00:47:38 +0100
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Subject: [PATCH] PCI: aardvark: Update comment about link going down after
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link-up
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Update the comment about what happens when link goes down after we have
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checked for link-up. If a PIO request is done while link-down, we have
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a serious problem.
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Signed-off-by: Marek Behún <kabel@kernel.org>
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---
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drivers/pci/controller/pci-aardvark.c | 8 ++++++--
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1 file changed, 6 insertions(+), 2 deletions(-)
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--- a/drivers/pci/controller/pci-aardvark.c
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+++ b/drivers/pci/controller/pci-aardvark.c
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2022-01-27 20:08:41 +08:00
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@@ -1005,8 +1005,12 @@ static bool advk_pcie_valid_device(struc
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2022-01-10 09:12:45 +08:00
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return false;
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/*
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- * If the link goes down after we check for link-up, nothing bad
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- * happens but the config access times out.
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+ * If the link goes down after we check for link-up, we have a problem:
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+ * if a PIO request is executed while link-down, the whole controller
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+ * gets stuck in a non-functional state, and even after link comes up
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+ * again, PIO requests won't work anymore, and a reset of the whole PCIe
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+ * controller is needed. Therefore we need to prevent sending PIO
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+ * requests while the link is down.
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*/
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if (!pci_is_root_bus(bus) && !advk_pcie_link_up(pcie))
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return false;
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