Using the hint from the plane state, we turn on the background color
to avoid display corruption from planes blending with the background.
Signed-off-by: Stefan Schake <stschake@xxxxxxxxx>
---
drivers/gpu/drm/vc4/vc4_crtc.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index ce1e3b9..728845f 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -643,9 +643,11 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
{
struct drm_device *dev = crtc->dev;
struct vc4_dev *vc4 = to_vc4_dev(dev);
+ struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
struct drm_plane *plane;
bool debug_dump_regs = false;
+ bool enable_bg_fill = false;
u32 __iomem *dlist_start = vc4->hvs->dlist + vc4_state->mm.start;
u32 __iomem *dlist_next = dlist_start;
@@ -656,6 +658,18 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
/* Copy all the active planes' dlist contents to the hardware dlist. */
drm_atomic_crtc_for_each_plane(plane, crtc) {
+ /* Is this the first active plane? */
+ if (dlist_next == dlist_start)
+ /* We need to enable background fill when a plane
+ * could be alpha blending from the background, i.e.
+ * where no other plane is underneath. It suffices to
+ * consider the first active plane here since we set
+ * needs_bg_fill such that either the first plane
+ * already needs it or all planes on top blend from
+ * the first or a lower plane.
+ */
+ enable_bg_fill = to_vc4_plane(plane)->needs_bg_fill;
+
dlist_next += vc4_plane_write_dlist(plane, dlist_next);
}
@@ -664,6 +678,14 @@ static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size);
+ if (enable_bg_fill)
+ /* This sets a black background color fill, as is the case
+ * with other DRM drivers.
+ */
+ HVS_WRITE(SCALER_DISPBKGNDX(vc4_crtc->channel),
+ HVS_READ(SCALER_DISPBKGNDX(vc4_crtc->channel)) |
+ SCALER_DISPBKGND_FILL);
+
/* Only update DISPLIST if the CRTC was already running and is not
* being disabled.
* vc4_crtc_enable() takes care of updating the dlist just after
--
2.7.4
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