drm/tegra: Split DC_CMD_STATE_CONTROL register write

The Tegra TRM says that the ACT_REQ and UPDATE fields cannot be
programmed at the same time so they are updated in two consecutive
writes instead.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index c5d825fd25fe..20864002cf39 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -689,9 +689,10 @@ static void tegra_crtc_commit(struct drm_crtc *crtc)
         struct tegra_dc *dc = to_tegra_dc(crtc);
         unsigned long value;
 
-        value = GENERAL_ACT_REQ | WIN_A_ACT_REQ |
-                GENERAL_UPDATE | WIN_A_UPDATE;
+        value = GENERAL_UPDATE | WIN_A_UPDATE;
+        tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
 
+        value = GENERAL_ACT_REQ | WIN_A_ACT_REQ;
         tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
 
         drm_vblank_post_modeset(crtc->dev, dc->pipe);