drm/fb-helper: Restore damage area upon errors

If the damage handling fails, restore the damage area. The next invocation
of the damage worker will then perform the update.

v3:
	* Use drm_WARN_ONCE() with an error message to print warning
v2:
	* print a single warning if dirty callback fails (Daniel, Sebastian)
	* update comment

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-9-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index fc709bc..3143526 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -432,11 +432,28 @@ static void drm_fb_helper_damage_work(struct work_struct *work)
        if (helper->buffer) {
                ret = drm_fb_helper_damage_blit(helper, &clip_copy);
                if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
-                       return;
+                       goto err;
+       }
+
+       if (helper->fb->funcs->dirty) {
+               ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1);
+               if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
+                       goto err;
        }
 
-       if (helper->fb->funcs->dirty)
-               helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, &clip_copy, 1);
+       return;
+
+err:
+       /*
+        * Restore damage clip rectangle on errors. The next run
+        * of the damage worker will perform the update.
+        */
+       spin_lock_irqsave(&helper->damage_lock, flags);
+       clip->x1 = min_t(u32, clip->x1, clip_copy.x1);
+       clip->y1 = min_t(u32, clip->y1, clip_copy.y1);
+       clip->x2 = max_t(u32, clip->x2, clip_copy.x2);
+       clip->y2 = max_t(u32, clip->y2, clip_copy.y2);
+       spin_unlock_irqrestore(&helper->damage_lock, flags);
 }
 
 /**