Re: [v2,2/8] video: Provide screen_info_get_pci_dev() to find screen_info's PCI device

[Sui Jingfeng <sui.jingfeng@xxxxxxxxx>]

Hi,


On 2024/2/2 19:58, Thomas Zimmermann wrote:
> diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c
> new file mode 100644
> index 0000000000000..d959a4c6ba3d5
> --- /dev/null
> +++ b/drivers/video/screen_info_pci.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/pci.h>
> +#include <linux/screen_info.h>
> +
> +static struct pci_dev *__screen_info_pci_dev(struct resource *res)
> +{
> +	struct pci_dev *pdev;
> +
> +	if (!(res->flags & IORESOURCE_MEM))
> +		return NULL;
> +
> +	for_each_pci_dev(pdev) {
> +		const struct resource *r;
> +
> +		if ((pdev->class >> 16) != PCI_BASE_CLASS_DISPLAY)
> +			continue;
> +
> +		r = pci_find_resource(pdev, res);
> +		if (r)
> +			return pdev;
> +	}
> +
> +	return NULL;
> +}


I recommend using the pci_get_base_class() or pci_get_class() helper function at here,
for example:


static struct pci_dev *__screen_info_pci_dev(struct resource *res)
{
	struct pci_dev *pdev;

	if (!(res->flags & IORESOURCE_MEM))
		return NULL;

	while ((pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {
		if (pci_find_resource(pdev, res))
			return pdev;
	}

	return NULL;
}