linux-kernel - Re: [PATCH v6 1/2] PCI: Add a helper to check Power Resource Requirements

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Date:   Fri, 18 Oct 2019 16:30:11 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/2] PCI: Add a helper to check Power Resource
 Requirements _PR3 existence



> On Oct 18, 2019, at 16:18, Takashi Iwai <tiwai@...e.de> wrote:
> 
> On Fri, 18 Oct 2019 09:38:47 +0200,
> Kai-Heng Feng wrote:
>> 
>> A driver may want to know the existence of _PR3, to choose different
>> runtime suspend behavior. A user will be add in next patch.
>> 
>> This is mostly the same as nouveau_pr3_present().
>> 
>> Reported-by: kbuild test robot <lkp@...el.com>
> 
> It's confusing -- this particular change isn't reported by the test
> bot, but only about the lack of the CONFIG_ACPI ifdef.

Hmm, because the test bot asked to add the tag.
If it's not appropriate will you drop it? I can also send a v7.

Kai-Heng

> 
> 
> thanks,
> 
> Takashi
> 
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>> ---
>> v6:
>> - Only define the function when CONFIG_ACPI is set.
>> v5:
>> - Add wording suggestion from Bjorn.
>> v4:
>> - Let caller to find its upstream port device.
>> 
>> drivers/pci/pci.c   | 18 ++++++++++++++++++
>> include/linux/pci.h |  2 ++
>> 2 files changed, 20 insertions(+)
>> 
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index e7982af9a5d8..1df99d9e350e 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -5856,6 +5856,24 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode,
>> 	return 0;
>> }
>> 
>> +#ifdef CONFIG_ACPI
>> +bool pci_pr3_present(struct pci_dev *pdev)
>> +{
>> +	struct acpi_device *adev;
>> +
>> +	if (acpi_disabled)
>> +		return false;
>> +
>> +	adev = ACPI_COMPANION(&pdev->dev);
>> +	if (!adev)
>> +		return false;
>> +
>> +	return adev->power.flags.power_resources &&
>> +		acpi_has_method(adev->handle, "_PR3");
>> +}
>> +EXPORT_SYMBOL_GPL(pci_pr3_present);
>> +#endif
>> +
>> /**
>>  * pci_add_dma_alias - Add a DMA devfn alias for a device
>>  * @dev: the PCI device for which alias is added
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index f9088c89a534..1d15c5d49cdd 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -2310,9 +2310,11 @@ struct irq_domain *pci_host_bridge_acpi_msi_domain(struct pci_bus *bus);
>> 
>> void
>> pci_msi_register_fwnode_provider(struct fwnode_handle *(*fn)(struct device *));
>> +bool pci_pr3_present(struct pci_dev *pdev);
>> #else
>> static inline struct irq_domain *
>> pci_host_bridge_acpi_msi_domain(struct pci_bus *bus) { return NULL; }
>> +static bool pci_pr3_present(struct pci_dev *pdev) { return false; }
>> #endif
>> 
>> #ifdef CONFIG_EEH
>> -- 
>> 2.17.1
>>