Our device need to have landscape and portrait display settings. So far we set the x11 rotation with xorg and is working fine. x11 uses the vivante driver. But after rotation the performance is reduced and we can see increased cpu usage. We have touch interface which is also rotated with x11. Same issue was reported Reduced graphic performance with rotated screen (imx6, sabresd) . Couldn't find any correct answer in which commit/release it was resolved. we are using the same 3.14 kernel and issue is there.
This is very critical for us and would welcome any suggestions/answers