Merge tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm

[uclinux-h8/linux.git] / drivers / video / fbdev / core / fbmem.c

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 8df3ac9..34d6bb1 100644 (file)
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/linux_logo.h>
 #include <linux/proc_fs.h>
+#include <linux/platform_device.h>
 #include <linux/seq_file.h>
 #include <linux/console.h>
 #include <linux/kmod.h>
@@ -1555,18 +1556,36 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
        /* check all firmware fbs and kick off if the base addr overlaps */
        for_each_registered_fb(i) {
                struct apertures_struct *gen_aper;
+               struct device *device;
 
                if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
                        continue;
 
                gen_aper = registered_fb[i]->apertures;
+               device = registered_fb[i]->device;
                if (fb_do_apertures_overlap(gen_aper, a) ||
                        (primary && gen_aper && gen_aper->count &&
                         gen_aper->ranges[0].base == VGA_FB_PHYS)) {
 
                        printk(KERN_INFO "fb%d: switching to %s from %s\n",
                               i, name, registered_fb[i]->fix.id);
-                       do_unregister_framebuffer(registered_fb[i]);
+
+                       /*
+                        * If we kick-out a firmware driver, we also want to remove
+                        * the underlying platform device, such as simple-framebuffer,
+                        * VESA, EFI, etc. A native driver will then be able to
+                        * allocate the memory range.
+                        *
+                        * If it's not a platform device, at least print a warning. A
+                        * fix would add code to remove the device from the system.
+                        */
+                       if (dev_is_platform(device)) {
+                               registered_fb[i]->forced_out = true;
+                               platform_device_unregister(to_platform_device(device));
+                       } else {
+                               pr_warn("fb%d: cannot remove device\n", i);
+                               do_unregister_framebuffer(registered_fb[i]);
+                       }
                }
        }
 }
@@ -1896,9 +1915,13 @@ EXPORT_SYMBOL(register_framebuffer);
 void
 unregister_framebuffer(struct fb_info *fb_info)
 {
-       mutex_lock(&registration_lock);
+       bool forced_out = fb_info->forced_out;
+
+       if (!forced_out)
+               mutex_lock(&registration_lock);
        do_unregister_framebuffer(fb_info);
-       mutex_unlock(&registration_lock);
+       if (!forced_out)
+               mutex_unlock(&registration_lock);
 }
 EXPORT_SYMBOL(unregister_framebuffer);