target/linux/generic/pending-5.10/850-0022-PCI-aardvark-Update-comment-about-link-going-down-af.patch

   1 From bafda858364003a70b9cda84282f9761587f8033 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
   3 Date: Mon, 10 Jan 2022 00:47:38 +0100
   4 Subject: [PATCH] PCI: aardvark: Update comment about link going down after
   5  link-up
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 Update the comment about what happens when link goes down after we have
  11 checked for link-up. If a PIO request is done while link-down, we have
  12 a serious problem.
  13
  14 Signed-off-by: Marek Behún <kabel@kernel.org>
  15 ---
  16  drivers/pci/controller/pci-aardvark.c | 8 ++++++--
  17  1 file changed, 6 insertions(+), 2 deletions(-)
  18
  19 diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
  20 index aa5629b8b5c9..3c0b6b931061 100644
  21 --- a/drivers/pci/controller/pci-aardvark.c
  22 +++ b/drivers/pci/controller/pci-aardvark.c
  23 @@ -1003,8 +1003,12 @@ static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
  24                 return false;
  25
  26         /*
  27 -        * If the link goes down after we check for link-up, nothing bad
  28 -        * happens but the config access times out.
  29 +        * If the link goes down after we check for link-up, we have a problem:
  30 +        * if a PIO request is executed while link-down, the whole controller
  31 +        * gets stuck in a non-functional state, and even after link comes up
  32 +        * again, PIO requests won't work anymore, and a reset of the whole PCIe
  33 +        * controller is needed. Therefore we need to prevent sending PIO
  34 +        * requests while the link is down.
  35          */
  36         if (!pci_is_root_bus(bus) && !advk_pcie_link_up(pcie))
  37                 return false;
  38 --
  39 2.34.1
  40