[PATCH 2/3] drm/i915/frontbuffer: HW tracking for cursor moves to fix PSR lags.

[Dhinakaran Pandiyan]

DRM_IOCTL_MODE_CURSOR results in frontbuffer flush before the cursor
plane MMIOs are written to. But this flush should not be necessary for
PSR as hardware tracking triggers PSR exit when MMIOs are written. As
for FBC, the spec says "Flips or changes to plane size and panning" cause
FBC to be nuked. Use origin == ORIGIN_FLIP so that features can ignore
cursor updates in their frontbuffer_flush implementations.

 /sys/kernel/debug/dri/0/i915_fbc_status shows
"Compressing: yes" when I move the cursor around.

v3: Use ORIGIN_FLIP now that pin_to_display does not flush frontbuffer.
v2: Update comment in i915_gem_object_pin_to_display_plane. (Chris)

Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 91ce8a0522a3..18b08e263ee1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13176,7 +13176,7 @@ intel_legacy_cursor_update(struct drm_plane *plane,
 	if (ret)
 		goto out_unlock;
 
-	intel_fb_obj_flush(intel_fb_obj(fb), ORIGIN_DIRTYFB);
+	intel_fb_obj_flush(intel_fb_obj(fb), ORIGIN_FLIP);
 
 	old_fb = old_plane_state->fb;
 	i915_gem_track_fb(intel_fb_obj(old_fb), intel_fb_obj(fb),
-- 
2.14.1