On Sat, Oct 3, 2026 at 5:31 AM Dave Klotz <[email protected]> wrote:
>
> The root port advertises ASPM L1 support in its Link Capabilities, so
> software that configures ASPM from what the port reports, such as an
> EFI application or an operating system that does not reinitialise the
> controller, may put the link into L1.
>
> Linux's pcie-spacemit-k1 driver clears PCI_EXP_LNKCAP_ASPM_L1 at init,
> as a workaround for errors reported on some NVMe drives. Do the same
> before link training starts, so the port is set up as Linux sets it up.
>
> Signed-off-by: Dave Klotz <[email protected]>
> ---
> drivers/pci/pcie_dw_spacemit.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/pci/pcie_dw_spacemit.c b/drivers/pci/pcie_dw_spacemit.c
> index 6ac1d6bea4..3b5c2dc4e0 100644
> --- a/drivers/pci/pcie_dw_spacemit.c
> +++ b/drivers/pci/pcie_dw_spacemit.c
> @@ -71,6 +71,12 @@ static void pcie_dw_configure(struct pcie_dw_spacemit *pci)
>
> dw_pcie_dbi_write_enable(&pci->dw, true);
>
> + /*
> + * Do not advertise ASPM L1: as Linux's driver notes, some NVMe drives
> + * report errors with it.
> + */
> + clrbits_le32(cap + PCI_EXP_LNKCAP, PCI_EXP_LNKCAP_ASPM_L1);
> +
> /*
> * Keep the hardware's supported speeds unless the device tree limits
> * them with "max-link-speed", as Linux's DesignWare core does.
> --
> 2.55.0
>
>
Reviewed-by: Eric Chung <[email protected]>
