drm/fbdev-helper: Set and clear VGA switcheroo client from fb_info

Call vga_switcheroo_client_fb_set() with the PCI device from the
instance of struct fb_info. All fbdev clients now run these calls.
For non-PCI devices or drivers without vga-switcheroo, this does
nothing. For i915 and radeon, it allows these drivers to use a
common fbdev client.

The device is the same as the one stored in struct drm_client and
struct drm_fb_helper, so there is no difference in behavior. Some
NULL-pointer checks are being removed, where those pointers cannot
be NULL.

v4:
- clarify call semantics for drm_fb_helper_unregister_info() (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-3-tzimmermann@suse.de

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index af1fe79c701d..550fa69311cb 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -554,7 +554,7 @@ EXPORT_SYMBOL(drm_fb_helper_release_info);
 
 /**
  * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
- * @fb_helper: driver-allocated fbdev helper, can be NULL
+ * @fb_helper: driver-allocated fbdev helper, must not be NULL
  *
  * A wrapper around unregister_framebuffer, to release the fb_info
  * framebuffer device. This must be called before releasing all resources for
@@ -562,8 +562,12 @@ EXPORT_SYMBOL(drm_fb_helper_release_info);
  */
 void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
 {
-	if (fb_helper && fb_helper->info)
-		unregister_framebuffer(fb_helper->info);
+	struct fb_info *info = fb_helper->info;
+	struct device *dev = info->device;
+
+	if (dev_is_pci(dev))
+		vga_switcheroo_client_fb_set(to_pci_dev(dev), NULL);
+	unregister_framebuffer(fb_helper->info);
 }
 EXPORT_SYMBOL(drm_fb_helper_unregister_info);
 
@@ -1615,6 +1619,7 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
 	struct drm_client_dev *client = &fb_helper->client;
 	struct drm_device *dev = fb_helper->dev;
 	struct drm_fb_helper_surface_size sizes;
+	struct fb_info *info;
 	int ret;
 
 	ret = drm_fb_helper_find_sizes(fb_helper, &sizes);
@@ -1632,9 +1637,11 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
 
 	strcpy(fb_helper->fb->comm, "[fbcon]");
 
+	info = fb_helper->info;
+
 	/* Set the fb info for vgaswitcheroo clients. Does nothing otherwise. */
-	if (dev_is_pci(dev->dev))
-		vga_switcheroo_client_fb_set(to_pci_dev(dev->dev), fb_helper->info);
+	if (dev_is_pci(info->device))
+		vga_switcheroo_client_fb_set(to_pci_dev(info->device), info);
 
 	return 0;
 }