quoted

+	struct drm_modeset_acquire_ctx ctx;
 	int i, r;
+	int ret;

Could you please tuck this up with i & r?

Done!

quoted

-	drm_modeset_unlock_all(dev);
+	DRM_MODESET_LOCK_ALL_END(dev, ctx, ret);

You should check ret here

Would it be save to return at this point if the lock fails?

In other words, can I just add this? --> "if (ret) return ret;"

quoted

+	struct drm_modeset_acquire_ctx ctx;
 	int r;
+	int ret;

Same suggestion here, move up with r

Done!

quoted

-		drm_modeset_unlock_all(dev);
+		DRM_MODESET_LOCK_ALL_END(dev, ctx, ret);

Also check ret here

Same question. Would "if (ret) return ret;" be safe here?

quoted

 	int i;
+	int ret;

Move up with i

Done!

quoted

-	drm_modeset_unlock_all(dev);
+	DRM_MODESET_LOCK_ALL_END(dev, ctx, ret);
 	return 0;

I can also "return ret;" instead of "0".

What happens when a DEFINE_SHOW_ATTRIBUTE'd function returns non-zero? Is it ok?
Or do we want to always return "0" to print whatever we can?