linux-kernel - Re: [PATCH V2 2/2] platform/x86/intel/pmc/mtl: Put devices in D3 during resume

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Message-ID: <c3e2ea9f-7971-9946-50e7-e7fa83fe5231@redhat.com>
Date:   Tue, 13 Jun 2023 12:29:09 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     david.e.box@...ux.intel.com, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org
Cc:     markgross@...nel.org, irenic.rajneesh@...il.com,
        ilpo.jarvinen@...ux.intel.com, xi.pardee@...el.com,
        rajvi.jingar@...ux.intel.com
Subject: Re: [PATCH V2 2/2] platform/x86/intel/pmc/mtl: Put devices in D3
 during resume

Hi,

On 6/12/23 20:02, David E. Box wrote:
> Hi Hans,
> 
> On Mon, 2023-06-12 at 11:42 +0200, Hans de Goede wrote:
>> Hi David,
>>
>> On 6/8/23 01:38, David E. Box wrote:
>>> An earlier commit placed some driverless devices in D3 during boot so that
>>> they don't block package cstate entry on Meteor Lake. 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>
>>
>> Thank you for your patch.
>>
>> There is one thing which has me worried here:
>>
>> What about when real proper drivers show up for these blocks?
>>
>> I know that at least some people will likely be using the out of tree IPU6
>> driver with the IPU block.
>>
>> And having 2 different drivers poke at the hw state seems like a bad idea to
>> me.
>>
>> Maybe we can add a check if no driver is bound and only set the state to D3 if
>> no driver is bound?
> 
> This check exists but is not shown in the patch. mtl_set_device_d3() gets the
> device lock and checks to see if dev.driver is NULL before putting in D3. This
> was checked with the GNA driver installed.

Ah, yes I remember this now from the original patch adding
mtl_set_device_d3(). Good.

Let me go and merge this right away then.

Regards,

Hans






>>> ---
>>>
>>> V2 - rename mtl_fixup to mtl_d3_fixup. Call it from new mtl_resume
>>>      function, followed by the common resume. Suggested by Ilpo.
>>>
>>>  drivers/platform/x86/intel/pmc/mtl.c | 29 ++++++++++++++++++++--------
>>>  1 file changed, 21 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/platform/x86/intel/pmc/mtl.c
>>> b/drivers/platform/x86/intel/pmc/mtl.c
>>> index e8cc156412ce..2b00ad9da621 100644
>>> --- a/drivers/platform/x86/intel/pmc/mtl.c
>>> +++ b/drivers/platform/x86/intel/pmc/mtl.c
>>> @@ -68,16 +68,29 @@ static void mtl_set_device_d3(unsigned int device)
>>>         }
>>>  }
>>>  
>>> -void mtl_core_init(struct pmc_dev *pmcdev)
>>> +/*
>>> + * Set power state of select devices that do not have drivers to D3
>>> + * so that they do not block Package C entry.
>>> + */
>>> +static void mtl_d3_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.
>>> -        */
>>>         mtl_set_device_d3(MTL_GNA_PCI_DEV);
>>>         mtl_set_device_d3(MTL_IPU_PCI_DEV);
>>>         mtl_set_device_d3(MTL_VPU_PCI_DEV);
>>>  }
>>> +
>>> +static int mtl_resume(struct pmc_dev *pmcdev)
>>> +{
>>> +       mtl_d3_fixup();
>>> +       return pmc_core_resume_common(pmcdev);
>>> +}
>>> +
>>> +void mtl_core_init(struct pmc_dev *pmcdev)
>>> +{
>>> +       pmcdev->map = &mtl_reg_map;
>>> +       pmcdev->core_configure = mtl_core_configure;
>>> +
>>> +       mtl_d3_fixup();
>>> +
>>> +       pmcdev->resume = mtl_resume;
>>> +}
>>
>