board/freescale/imx6-sabresd: improve Qt5 Cinematic Demo instructions

QT_QPA_EGLFS_ALWAYS_SET_MODE=1 needs to be exported, otherwise the Qt5
Cinematic demo throws a storm of the following messages:

Could not queue DRM page flip on screen LVDS1 (Invalid argument)

Improve the instructions by mentioning such requirement.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

diff --git a/board/freescale/imx6-sabresd/readme.txt b/board/freescale/imx6-sabresd/readme.txt
index f09ff5caf44e7efaf935ed40757e7090476103e3..292dab72c43c78eafceebcc641b3a7bef60e7359 100644 (file)
--- a/board/freescale/imx6-sabresd/readme.txt
+++ b/board/freescale/imx6-sabresd/readme.txt
@@ -80,6 +80,7 @@ Running kmscube application:
 Running Qt5 Cinematic Demo:
 
 # export QT_QPA_EGLFS_KMS_CONFIG=/root/sabresd.json
+# export QT_QPA_EGLFS_ALWAYS_SET_MODE=1
 # /usr/share/Qt5/CinematicExperience/Qt5_CinematicExperience
 
 Running gl2mark benchmark: