[PATCH hwc] drm_hwcomposer: fix return values for ValidateDisplay

[Rob Herring]

According to the API documentation, if we've set num_types, then the
return value should be HWC2::Error::HasChanges.

Signed-off-by: Rob Herring <robh at kernel.org>
---
 drmhwctwo.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drmhwctwo.cpp b/drmhwctwo.cpp
index 89399bf1ba33..0f258770a8bb 100644
--- a/drmhwctwo.cpp
+++ b/drmhwctwo.cpp
@@ -701,7 +701,7 @@ HWC2::Error DrmHwcTwo::HwcDisplay::ValidateDisplay(uint32_t *num_types,
         break;
     }
   }
-  return HWC2::Error::None;
+  return *num_types ? HWC2::Error::HasChanges : HWC2::Error::None;
 }
 
 HWC2::Error DrmHwcTwo::HwcLayer::SetCursorPosition(int32_t x, int32_t y) {
-- 
2.11.0