From: Bjorn Helgaas <helgaas@kernel.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI/PME: Replace RMW of Root Status register with direct write
Date: Fri, 6 Feb 2026 16:42:35 -0600 [thread overview]
Message-ID: <20260206224235.GA99608@bhelgaas> (raw)
In-Reply-To: <39f87c99f6c44be3c0371c79e454e6fde7be0d4d.1761497583.git.lukas@wunner.de>
On Sun, Oct 26, 2025 at 05:57:57PM +0100, Lukas Wunner wrote:
> As of PCIe r7.0, the Root Status register contains a single writeable bit
> (PME Status, type RW1C) and otherwise just read-only bits and RsvdZ bits
> (which software must write as zero, PCIe r7.0 sec 7.4).
>
> Thus, when clearing the PME Status bit, there's no need to perform a
> read-modify-write of the register. Instead, the bit can be written
> directly.
>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
Applied to pci/enumeration for v6.20, thanks!
Thanks for the ping; I don't remember but suspect I just bulk-archived
old things in patchwork because it was so overwhelming.
> ---
> drivers/pci/pci.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b14dd064006c..411a0b88841e 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2285,7 +2285,7 @@ void pcie_clear_device_status(struct pci_dev *dev)
> */
> void pcie_clear_root_pme_status(struct pci_dev *dev)
> {
> - pcie_capability_set_dword(dev, PCI_EXP_RTSTA, PCI_EXP_RTSTA_PME);
> + pcie_capability_write_dword(dev, PCI_EXP_RTSTA, PCI_EXP_RTSTA_PME);
> }
>
> /**
> --
> 2.51.0
>
prev parent reply other threads:[~2026-02-06 22:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-26 16:57 [PATCH] PCI/PME: Replace RMW of Root Status register with direct write Lukas Wunner
2026-01-22 9:01 ` Lukas Wunner
2026-01-22 10:22 ` Ilpo Järvinen
2026-02-06 22:42 ` Bjorn Helgaas [this message]
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