Re: [PATCH v8 4/9] PCI: Add additional checks for flr reset

Julian Ruess
2026-01-26T13:11:47Z

On Thu Jan 22, 2026 at 8:44 PM CET, Farhan Ali wrote:
> If a device is in an error state, then any reads of device registers can
> return error value. Add addtional checks to validate if a device is in an

typo: additional

> error state before doing an flr reset.
>
> Cc: stable@vger.kernel.org
> Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
> drivers/pci/pci.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index e7beaf1f65a7..2d0a4c7714af 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4358,12 +4358,19 @@ EXPORT_SYMBOL_GPL(pcie_flr);
> */
> int pcie_reset_flr(struct pci_dev *dev, bool probe)
> {
> + u32 reg;
> +
> if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
> return -ENOTTY;
>
> if (!(dev->devcap & PCI_EXP_DEVCAP_FLR))
> return -ENOTTY;
>
> + if (pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &reg)) {
> + pci_warn(dev, "Device unable to do an FLR\n");
> + return -ENOTTY;
> + }
> +
> if (probe)
> return 0;
>