linux-kernel - Re: [PATCH v11 8/9] PCI: Split PME state selection into a local static function

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Message-ID: <c07aba63-6ca0-4889-aa98-30248f86c313@amd.com>
Date:   Thu, 10 Aug 2023 11:29:49 -0500
From:   "Limonciello, Mario" <mario.limonciello@....com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Bjorn Helgaas <helgaas@...nel.org>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Iain Lane <iain@...ngesquash.org.uk>,
        Shyam-sundar S-k <Shyam-sundar.S-k@....com>
Subject: Re: [PATCH v11 8/9] PCI: Split PME state selection into a local
 static function



On 8/10/2023 11:21 AM, Andy Shevchenko wrote:
> On Wed, Aug 09, 2023 at 01:54:52PM -0500, Mario Limonciello wrote:
>> When a device is not power manageable by the platform, and not already
>> in a low power state pci_target_state() will find the deepest state
>> that PME is supported and use this to select the wakeup state.
>>
>> Simplify this logic and split it out to a local function. No intended
>> functional changes.
> 
> ...
> 
>> +static inline pci_power_t pci_get_wake_pme_state(struct pci_dev *dev)
>> +{
>> +	pci_power_t state = PCI_D3hot;
>> +
>> +	while (state && !(dev->pme_support & (1 << state)))
>> +		state--;
>> +
>> +	return state;
> 
> Sparse won't be happy about this code (with CF=-D__CHECK_ENDIAN__).
> 
> Basically it's something like
> 
> 	return (__force pci_power_t)fls(dev->pme_support & GENMASK(PCI_D3hot, 0));
> 
> (but double check and test the logic).
> 
>> +}
> 
> ...
> 
> Yeah, I see that is the existing code, perhaps amend it first?
> 

Are you sure?  I actually double checked the sparse output using this 
command before I sent it.

make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' drivers/pci/pci.o

I didn't see anything related to the line numbers for this function.