Re: [PATCH v2] Add support for PCIe SSD status LED management

From: Lukas Wunner <lukas@wunner.de>
To: Stuart Hayes <stuart.w.hayes@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
	kw@linux.com
Subject: Re: [PATCH v2] Add support for PCIe SSD status LED management
Date: Wed, 2 Jun 2021 09:05:35 +0200	[thread overview]
Message-ID: <20210602070535.GA16825@wunner.de> (raw)
In-Reply-To: <20210601203820.3647-1-stuart.w.hayes@gmail.com>

On Tue, Jun 01, 2021 at 04:38:20PM -0400, Stuart Hayes wrote:
> --- /dev/null
> +++ b/drivers/pci/pcie-ssd-leds.c

Since this is a PCIe-specific feature, it should probably live in the
pcie/ subdirectory.  Or in drivers/nvme/.

> +static bool pdev_has_dsm(struct pci_dev *pdev)
> +{
> +	acpi_handle handle;
> +
> +	handle = ACPI_HANDLE(&pdev->dev);
> +	if (!handle)
> +		return false;
> +
> +	return acpi_check_dsm(handle, &pcie_ssdleds_dsm_guid, 0x1,
> +			      1 << GET_SUPPORTED_STATES_DSM ||
> +			      1 << GET_STATE_DSM ||
> +			      1 << SET_STATE_DSM);
> +}

Would it be possible to bail out early if pdev->class !=
PCI_CLASS_STORAGE_EXPRESS (or something like that), thus avoiding
the overhead of an ACPI namespace search for *every* PCI device?

Thanks,

Lukas