Re: [PATCH v3 10/23] drm/qxl: move qxl_primary_apply_cursor to correct place

quoted

The cursor must be set again after creating the primary surface.
Also drop the error message.

quoted

 	if (!bo->is_primary) {
-		if (!same_shadow)
+		if (!same_shadow) {
 			qxl_io_create_primary(qdev, 0, bo);
+			qxl_primary_apply_cursor(plane);
+		}
 		bo->is_primary = true;
 	}
 

I don't see how the commit message matches what you're doing. It gives
the impression that it must be applied under yet another condition, but
the condition for applying the cursor is changed from bo_old->is_primary
to !bo->is_primary.

The qxl device ties the cursor to the primary surface.  Therefore
calling qxl_io_destroy_primary() and qxl_io_create_primary() to switch
the framebuffer causes the cursor information being lost and the driver
must re-apply it.

The correct call order to do that is qxl_io_destroy_primary() +
qxl_io_create_primary() + qxl_primary_apply_cursor().

The old code did qxl_io_destroy_primary() + qxl_primary_apply_cursor() +
qxl_io_create_primary().  Due to qxl_primary_apply_cursor request being
queued in a ringbuffer and qxl_io_create_primary() trapping to the
hypervisor instantly there is a high chance that qxl_io_create_primary()
is processed first even with the wrong call order.  But it's racy and
thus not reliable.

It probably makes sense to someone that knows the driver.

If the above explains things better to you I should probably replace the
commit message with that.

Acked-by: Noralf Trønnes <redacted>

thanks,
  Gerd