[Intel-gfx] [PATCH 2/2] drm/i915: Calculate vlv/chv intermediate watermarks correctly

[Maarten Lankhorst]

The watermarks it should calculate against are the old optimal watermarks.
The currently active crtc watermarks are pure fiction, and are invalid in
case of a nonblocking modeset, page flip enabling/disabling planes or any
other reason.

When the crtc is disabled or during a modeset the intermediate watermarks
don't need to be programmed separately, and could be directly assigned
to the optimal watermarks.

Also rename crtc_state to new_crtc_state, to distinguish it from the old state.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7da701dc3caa..9ee73ef1dd1b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -1458,16 +1458,24 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state,
 
 static int vlv_compute_intermediate_wm(struct drm_device *dev,
 				       struct intel_crtc *crtc,
-				       struct intel_crtc_state *crtc_state)
+				       struct intel_crtc_state *new_crtc_state)
 {
-	struct vlv_wm_state *intermediate = &crtc_state->wm.vlv.intermediate;
-	const struct vlv_wm_state *optimal = &crtc_state->wm.vlv.optimal;
-	const struct vlv_wm_state *active = &crtc->wm.active.vlv;
+	struct vlv_wm_state *intermediate = &new_crtc_state->wm.vlv.intermediate;
+	const struct vlv_wm_state *optimal = &new_crtc_state->wm.vlv.optimal;
+	const struct drm_crtc_state *old_drm_crtc_state =
+		drm_atomic_get_old_crtc_state(new_crtc_state->base.state, &crtc->base);
+	const struct vlv_wm_state *active = &to_intel_crtc_state(old_drm_crtc_state)->wm.vlv.optimal;
 	int level;
 
+	if (!new_crtc_state->base.active || drm_atomic_crtc_needs_modeset(&new_crtc_state->base)) {
+		*intermediate = *optimal;
+
+		return 0;
+	}
+
 	intermediate->num_levels = min(optimal->num_levels, active->num_levels);
 	intermediate->cxsr = optimal->cxsr && active->cxsr &&
-		!crtc_state->disable_cxsr;
+		!new_crtc_state->disable_cxsr;
 
 	for (level = 0; level < intermediate->num_levels; level++) {
 		enum plane_id plane_id;
@@ -1491,7 +1499,7 @@ static int vlv_compute_intermediate_wm(struct drm_device *dev,
 	 * omit the post-vblank programming; only update if it's different.
 	 */
 	if (memcmp(intermediate, optimal, sizeof(*intermediate)) != 0)
-		crtc_state->wm.need_postvbl_update = true;
+		new_crtc_state->wm.need_postvbl_update = true;
 
 	return 0;
 }
-- 
2.7.4