[Intel-gfx] [PATCH 2/2] drm/i915: Recompute WM when the cursor size changes

[Chris Wilson]

If the cursor width is changed, we may need to recompute our WM to
prevent untold flickering. We hope that the registers are flushed on the
same vblank to prevent underruns...

Cc: Damien Lespiau <damien.lespiau at intel.com>
Cc: Sagar Kamble <sagar.a.kamble at intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_display.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c8c52d105b8c..e15b3abe1350 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7763,6 +7763,7 @@ static int intel_crtc_cursor_set(struct drm_crtc *crtc,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct drm_i915_gem_object *obj;
+	unsigned old_width;
 	uint32_t addr;
 	int ret;
 
@@ -7853,13 +7854,18 @@ static int intel_crtc_cursor_set(struct drm_crtc *crtc,
 
 	mutex_unlock(&dev->struct_mutex);
 
+	old_width = intel_crtc->cursor_width;
+
 	intel_crtc->cursor_addr = addr;
 	intel_crtc->cursor_bo = obj;
 	intel_crtc->cursor_width = width;
 	intel_crtc->cursor_height = height;
 
-	if (intel_crtc->active)
+	if (intel_crtc->active) {
+		if (old_width != width)
+			intel_update_watermarks(crtc);
 		intel_crtc_update_cursor(crtc, intel_crtc->cursor_bo != NULL);
+	}
 
 	return 0;
 fail_unpin:
-- 
1.9.1