linux-kernel - Re: [PATCH 2/2] platform/x86/intel/pmc/mtl: Put devices in D3 during resume

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Date:   Mon, 5 Jun 2023 14:59:24 +0300 (EEST)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     "David E. Box" <david.e.box@...ux.intel.com>
cc:     irenic.rajneesh@...il.com, hdegoede@...hat.com,
        markgross@...nel.org, platform-driver-x86@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] platform/x86/intel/pmc/mtl: Put devices in D3 during
 resume

On Fri, 2 Jun 2023, David E. Box wrote:

> An earlier commit placed some driverless devices in D3 during boot so that
> they don't block package cstate entry. Also place these devices in D3 after
> resume from suspend.
> 
> Fixes: 336ba968d3e3 ("platform/x86/intel/pmc/mtl: Put GNA/IPU/VPU devices in D3")
> Signed-off-by: David E. Box <david.e.box@...ux.intel.com>
> ---
>  drivers/platform/x86/intel/pmc/mtl.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/mtl.c b/drivers/platform/x86/intel/pmc/mtl.c
> index e8cc156412ce..d87c4597c6d4 100644
> --- a/drivers/platform/x86/intel/pmc/mtl.c
> +++ b/drivers/platform/x86/intel/pmc/mtl.c
> @@ -68,11 +68,8 @@ static void mtl_set_device_d3(unsigned int device)
>  	}
>  }
>  
> -void mtl_core_init(struct pmc_dev *pmcdev)
> +static void mtl_fixup(void)
>  {
> -	pmcdev->map = &mtl_reg_map;
> -	pmcdev->core_configure = mtl_core_configure;
> -
>  	/*
>  	 * Set power state of select devices that do not have drivers to D3
>  	 * so that they do not block Package C entry.
> @@ -81,3 +78,13 @@ void mtl_core_init(struct pmc_dev *pmcdev)
>  	mtl_set_device_d3(MTL_IPU_PCI_DEV);
>  	mtl_set_device_d3(MTL_VPU_PCI_DEV);

I'd prefer the function be called something related to d3 / power state / 
or some along those lines rather than something obscure such as 
mtl_fixup(). And you can move the comment to be a function comment now.

>  }
> +
> +void mtl_core_init(struct pmc_dev *pmcdev)
> +{
> +	pmcdev->map = &mtl_reg_map;
> +	pmcdev->core_configure = mtl_core_configure;
> +
> +	mtl_fixup();
> +
> +	pmcdev->resume_fixup = mtl_fixup;

I'm a bit on the edge here whether this is a good approach in long-term or 
if it would be better to just provide a way for the platform file to 
replace entire .resume() (for this task it's obviously enough but it 
feels a bit hacky to hook into one fixed place on resume path).

static __maybe_unused int pmc_core_resume(struct device *dev)
{
	if (pmcdev->resume)
		return pmcdev->resume();
	else
		return pmc_core_resume_common();
}

where pmc_core_resume_common() contains the current pmc_core_resume() 
contents.

mtl_resume() would just call the d3 func and the common resume functions.


-- 
 i.