Re: [PATCH v2] bus: mhi: host: pci_generic: Add missing poweroff() PM callback

[Manivannan Sadhasivam]

On Tue, Apr 05, 2022 at 06:29:07PM +0530, Manivannan Sadhasivam wrote:
> During hibernation process, once thaw() stage completes, the MHI endpoint
> devices will be in M0 state post recovery. After that, the devices will be
> powered down so that the system can enter the target sleep state. During
> this stage, the PCI core will put the devices in D3hot. But this transition
> is allowed by the MHI spec. The devices can only enter D3hot when it is in
> M3 state.
> 
> So for fixing this issue, let's add the poweroff() callback that will get
> executed before putting the system in target sleep state during
> hibernation. This callback will power down the device properly so that it
> could be restored during restore() or thaw() stage.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 5f0c2ee1fe8d ("bus: mhi: pci-generic: Fix hibernation")
> Reported-by: Hemant Kumar <quic_hemantk@xxxxxxxxxxx>
> Suggested-by: Hemant Kumar <quic_hemantk@xxxxxxxxxxx>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---

Applied to mhi-next!

Thanks,
Mani

> 
> Changes in v2:
> 
> * Hemant suggested to use restore function for poweroff() callback as we can
> make sure that the device gets powered down properly.
> 
>  drivers/bus/mhi/host/pci_generic.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> index 9527b7d63840..ef85dbfb3216 100644
> --- a/drivers/bus/mhi/host/pci_generic.c
> +++ b/drivers/bus/mhi/host/pci_generic.c
> @@ -1085,6 +1085,7 @@ static const struct dev_pm_ops mhi_pci_pm_ops = {
>  	.resume = mhi_pci_resume,
>  	.freeze = mhi_pci_freeze,
>  	.thaw = mhi_pci_restore,
> +	.poweroff = mhi_pci_freeze,
>  	.restore = mhi_pci_restore,
>  #endif
>  };
> -- 
> 2.25.1
>