Re: [PATCH] bus: mhi: host: pci_generic: Update the default autosuspend_delay_ms as 5000ms

[Loic Poulain]

On Mon, Oct 19, 2026 at 7:52 AM Slark Xiao <slark_xiao@xxxxxxx> wrote:
>
> For some MHI devices in some specific scenario, the default value
> of autosuspend_delay_ms may not enough to handle last wake event.
> This may lead to some unexpected problems.
>
> Refer to the Qualcomm's Windows settings and we checked this with
> Quaclomm over case, Qualcomm recommend us to set this as 5000ms.

Qualcomm

> Qualcomm also suggests us to update this for all MHI devices.
> Since this setting has affected some existed kernel versions, it's
> better to be applied to stable version.

This looks more like a workaround than a proper fix. It would be
helpful to describe the underlying issue, including the timing and
sequence of events that make this necessary. In principle, either the
device can be suspended at that point or it cannot. Relying on a
delayed suspend feels fragile and may end up masking the real problem.

>
> Fixes: d3800c1dce24 ("bus: mhi: pci_generic: Add support for runtime PM")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Slark Xiao <slark_xiao@xxxxxxx>
> ---
>  drivers/bus/mhi/host/pci_generic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> index 7193a384cca4..40735beb46cb 100644
> --- a/drivers/bus/mhi/host/pci_generic.c
> +++ b/drivers/bus/mhi/host/pci_generic.c
> @@ -1483,7 +1483,7 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
>         /* Allow runtime suspend only if both PME from D3Hot and M3 are supported */
>         if (pci_pme_capable(pdev, PCI_D3hot) && !(info->no_m3)) {
> -               pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
> +               pm_runtime_set_autosuspend_delay(&pdev->dev, 5000);
>                 pm_runtime_use_autosuspend(&pdev->dev);
>                 pm_runtime_mark_last_busy(&pdev->dev);
>                 pm_runtime_put_noidle(&pdev->dev);
> --
> 2.53.0
>