Merge tag 'drm-misc-next-2022-06-08' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for 5.20:

UAPI Changes:

 * connector: export bpc limits in debugfs

 * dma-buf: Print buffer name in debugfs

Cross-subsystem Changes:

 * dma-buf: Improve dma-fence handling; Cleanups

 * fbdev: Device-unregistering fixes

Core Changes:

 * client: Only use driver-validated modes to avoid blank screen

 * dp-aux: Make probing more reliable; Small fixes

 * edit: CEA data-block iterators; Introduce struct drm_edid; Many cleanups

 * gem: Don't use framebuffer format's non-exising color planes

 * probe-helper: Use 640x480 as DisplayPort fallback; Refactoring

 * scheduler: Don't kill jobs in interrupt context

Driver Changes:

 * amdgpu: Use atomic fence helpers in DM; Fix VRAM address calculation;
   Export CRTC bpc settings via debugfs

 * bridge: Add TI-DLPC3433;  anx7625: Fixes;  fy07024di26a30d: Optional
   GPIO reset;  icn6211: Cleanups;  ldb: Add reg and reg-name properties
   to bindings, Kconfig fixes;  lt9611: Fix display sensing;  lt9611uxc:
   Fixes;  nwl-dsi: Fixes;  ps8640: Cleanups;  st7735r: Fixes;  tc358767:
   DSI/DPI refactoring and DSI-to-eDP support, Fixes; ti-sn65dsi83:
   Fixes;

 * gma500: Cleanup connector I2C handling

 * hyperv: Unify VRAM allocation of Gen1 and Gen2

 * i915: export CRTC bpc settings via debugfs

 * meson: Support YUV422 output; Refcount fixes

 * mgag200: Support damage clipping; Support gamma handling; Protect
   concurrent HW access; Fixes to connector; Store model-specific limits
   in device-info structure; Cleanups

 * nouveau: Fixes and Cleanups

 * panel: Kconfig fixes

 * panfrost: Valhall support

 * r128: Fix bit-shift overflow

 * rockchip: Locking fixes in error path; Minor cleanups

 * ssd130x: Fix built-in linkage

 * ttm: Cleanups

 * udl; Always advertize VGA connector

 * fbdev/vesa: Support COMPILE_TEST

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YqBtumw05JZDEZE2@linux-uq9g

1 files changed, 15 insertions, 7 deletions

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index afa2863670f3..2a1a425ceb98 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1555,6 +1555,7 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
 {
 	int i;
 
+restart_removal:
 	/* check all firmware fbs and kick off if the base addr overlaps */
 	for_each_registered_fb(i) {
 		struct apertures_struct *gen_aper;
@@ -1587,12 +1588,23 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
 				pr_warn("fb%d: no device set\n", i);
 				do_unregister_framebuffer(registered_fb[i]);
 			} else if (dev_is_platform(device)) {
-				registered_fb[i]->forced_out = true;
+				/*
+				 * Drop the lock because if the device is unregistered, its
+				 * driver will call to unregister_framebuffer(), that takes
+				 * this lock.
+				 */
+				mutex_unlock(&registration_lock);
 				platform_device_unregister(to_platform_device(device));
+				mutex_lock(&registration_lock);
 			} else {
 				pr_warn("fb%d: cannot remove device\n", i);
 				do_unregister_framebuffer(registered_fb[i]);
 			}
+			/*
+			 * Restart the removal loop now that the device has been
+			 * unregistered and its associated framebuffer gone.
+			 */
+			goto restart_removal;
 		}
 	}
 }
@@ -1852,13 +1864,9 @@ EXPORT_SYMBOL(register_framebuffer);
 void
 unregister_framebuffer(struct fb_info *fb_info)
 {
-	bool forced_out = fb_info->forced_out;
-
-	if (!forced_out)
-		mutex_lock(&registration_lock);
+	mutex_lock(&registration_lock);
 	do_unregister_framebuffer(fb_info);
-	if (!forced_out)
-		mutex_unlock(&registration_lock);
+	mutex_unlock(&registration_lock);
 }
 EXPORT_SYMBOL(unregister_framebuffer);