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

[Sui Jingfeng]

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;
}