MTK DRM driver didn't set the vblank_disable_allowed to
true, it cause that the irq_handler is called every
16.6 ms (every vblank) when the display didn't be updated.

Signed-off-by: Bibby Hsieh <redacted>
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index eebb7d8..941ec5f 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c

@@ -200,6 +200,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
 	if (ret < 0)
 		goto err_component_unbind;
 
+	drm->vblank_disable_allowed = true;
 	drm_kms_helper_poll_init(drm);
 	drm_mode_config_reset(drm);