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Message-ID: <CAKF3qh0GUgnyxx4P7M8jtwPdPT0xTPBjBQU3j8sqwsYANJrLag@mail.gmail.com>
Date: Tue, 20 Oct 2020 16:33:14 +0800
From: Ethan Zhao <xerces.zhao@...il.com>
To: Sanjay R Mehta <Sanju.Mehta@....com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Lukas Wunner <lukas@...ner.de>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Stuart Hayes <stuart.w.hayes@...il.com>,
Alexandru Gagniuc <mr.nuke.me@...il.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] pciehp: Add check for DL_ACTIVE bit in pciehp_check_link_status()
On Tue, Oct 20, 2020 at 2:33 PM Sanjay R Mehta <Sanju.Mehta@....com> wrote:
>
> From: Sanjay R Mehta <sanju.mehta@....com>
>
> if DL_ACTIVE bit is set it means that there is no need to check
> PCI_EXP_LNKSTA_LT bit, as DL_ACTIVE would have set only if the link
> is already trained. Hence adding a check which takes care of this
> scenario.
Sorry, I couldn't understand the logic here. if DL_ACTIVE was set,
PCI_EXP_LNKSTA_LT is to be cleared, vice versa. why need
(lnk_status & PCI_EXP_LNKSTA_LT) &&
!(lnk_status & PCI_EXP_LNKSTA_DLLLA)
Double safe ?
Thanks,
Ethan
>
> Signed-off-by: Sanjay R Mehta <sanju.mehta@....com>
> ---
> drivers/pci/hotplug/pciehp_hpc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
> index 53433b37e181..8ab2f6a2f388 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -309,7 +309,8 @@ int pciehp_check_link_status(struct controller *ctrl)
>
> pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
> - if ((lnk_status & PCI_EXP_LNKSTA_LT) ||
> + if (((lnk_status & PCI_EXP_LNKSTA_LT) &&
> + !(lnk_status & PCI_EXP_LNKSTA_DLLLA)) ||
> !(lnk_status & PCI_EXP_LNKSTA_NLW)) {
> ctrl_err(ctrl, "link training error: status %#06x\n",
> lnk_status);
> --
> 2.25.1
>
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