[Intel-gfx] [PATCH] drm/i915/chv: Use 16 and 32 for low and high drain latency precision.

[Rodrigo Vivi]

Current chv spec teels we can only use either 16 or 32 bits as precision.

Although in the past VLV went from 16/32 to 32/64 and spec might not be updated,
these precision values brings stability and fixes some issues Wayne was facing.

Cc: Wayne Boyer <wayne.boyer at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h | 13 +++++++------
 drivers/gpu/drm/i915/intel_pm.c | 40 +++++++++++++++++++++++++---------------
 2 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6db369a..dcd5650 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4054,17 +4054,18 @@ enum punit_power_well {
 #define   DSPFW_PLANEA_WM1_HI_MASK	(1<<0)
 
 /* drain latency register values*/
+#define DRAIN_LATENCY_PRECISION_16	16
 #define DRAIN_LATENCY_PRECISION_32	32
 #define DRAIN_LATENCY_PRECISION_64	64
 #define VLV_DDL(pipe)			(VLV_DISPLAY_BASE + 0x70050 + 4 * (pipe))
-#define DDL_CURSOR_PRECISION_64		(1<<31)
-#define DDL_CURSOR_PRECISION_32		(0<<31)
+#define DDL_CURSOR_PRECISION_HIGH	(1<<31)
+#define DDL_CURSOR_PRECISION_LOW	(0<<31)
 #define DDL_CURSOR_SHIFT		24
-#define DDL_SPRITE_PRECISION_64(sprite)	(1<<(15+8*(sprite)))
-#define DDL_SPRITE_PRECISION_32(sprite)	(0<<(15+8*(sprite)))
+#define DDL_SPRITE_PRECISION_HIGH(sprite)	(1<<(15+8*(sprite)))
+#define DDL_SPRITE_PRECISION_LOW(sprite)	(0<<(15+8*(sprite)))
 #define DDL_SPRITE_SHIFT(sprite)	(8+8*(sprite))
-#define DDL_PLANE_PRECISION_64		(1<<7)
-#define DDL_PLANE_PRECISION_32		(0<<7)
+#define DDL_PLANE_PRECISION_HIGH	(1<<7)
+#define DDL_PLANE_PRECISION_LOW		(0<<7)
 #define DDL_PLANE_SHIFT			0
 #define DRAIN_LATENCY_MASK		0x7f
 
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index daa99e7..50c3512 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -1345,6 +1345,7 @@ static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
 				      int *prec_mult,
 				      int *drain_latency)
 {
+	struct drm_device *dev = crtc->dev;
 	int entries;
 	int clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
 
@@ -1355,8 +1356,12 @@ static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
 		return false;
 
 	entries = DIV_ROUND_UP(clock, 1000) * pixel_size;
-	*prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_64 :
-				       DRAIN_LATENCY_PRECISION_32;
+	if (IS_CHERRYVIEW(dev))
+		*prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_32 :
+					       DRAIN_LATENCY_PRECISION_16;
+	else
+		*prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_64 :
+					       DRAIN_LATENCY_PRECISION_32;
 	*drain_latency = (64 * (*prec_mult) * 4) / entries;
 
 	if (*drain_latency > DRAIN_LATENCY_MASK)
@@ -1375,15 +1380,18 @@ static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
 
 static void vlv_update_drain_latency(struct drm_crtc *crtc)
 {
-	struct drm_i915_private *dev_priv = crtc->dev->dev_private;
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pixel_size;
 	int drain_latency;
 	enum pipe pipe = intel_crtc->pipe;
 	int plane_prec, prec_mult, plane_dl;
+	int high_precision = IS_CHERRYVIEW(dev) ? DRAIN_LATENCY_PRECISION_32 :
+						  DRAIN_LATENCY_PRECISION_64;
 
-	plane_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_PLANE_PRECISION_64 |
-		   DRAIN_LATENCY_MASK | DDL_CURSOR_PRECISION_64 |
+	plane_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_PLANE_PRECISION_HIGH |
+		   DRAIN_LATENCY_MASK | DDL_CURSOR_PRECISION_HIGH |
 		   (DRAIN_LATENCY_MASK << DDL_CURSOR_SHIFT));
 
 	if (!intel_crtc_active(crtc)) {
@@ -1394,9 +1402,9 @@ static void vlv_update_drain_latency(struct drm_crtc *crtc)
 	/* Primary plane Drain Latency */
 	pixel_size = crtc->primary->fb->bits_per_pixel / 8;	/* BPP */
 	if (vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
-		plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
-					   DDL_PLANE_PRECISION_64 :
-					   DDL_PLANE_PRECISION_32;
+		plane_prec = (prec_mult == high_precision) ?
+					   DDL_PLANE_PRECISION_HIGH :
+					   DDL_PLANE_PRECISION_LOW;
 		plane_dl |= plane_prec | drain_latency;
 	}
 
@@ -1408,9 +1416,9 @@ static void vlv_update_drain_latency(struct drm_crtc *crtc)
 	/* Program cursor DL only if it is enabled */
 	if (intel_crtc->cursor_base &&
 	    vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
-		plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
-					   DDL_CURSOR_PRECISION_64 :
-					   DDL_CURSOR_PRECISION_32;
+		plane_prec = (prec_mult == high_precision) ?
+					   DDL_CURSOR_PRECISION_HIGH :
+					   DDL_CURSOR_PRECISION_LOW;
 		plane_dl |= plane_prec | (drain_latency << DDL_CURSOR_SHIFT);
 	}
 
@@ -1578,15 +1586,17 @@ static void valleyview_update_sprite_wm(struct drm_plane *plane,
 	int plane_prec;
 	int sprite_dl;
 	int prec_mult;
+	int high_precision = IS_CHERRYVIEW(dev) ? DRAIN_LATENCY_PRECISION_32 :
+						  DRAIN_LATENCY_PRECISION_64;
 
-	sprite_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_SPRITE_PRECISION_64(sprite) |
+	sprite_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_SPRITE_PRECISION_HIGH(sprite) |
 		    (DRAIN_LATENCY_MASK << DDL_SPRITE_SHIFT(sprite)));
 
 	if (enabled && vlv_compute_drain_latency(crtc, pixel_size, &prec_mult,
 						 &drain_latency)) {
-		plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
-					   DDL_SPRITE_PRECISION_64(sprite) :
-					   DDL_SPRITE_PRECISION_32(sprite);
+		plane_prec = (prec_mult == high_precision) ?
+					   DDL_SPRITE_PRECISION_HIGH(sprite) :
+					   DDL_SPRITE_PRECISION_LOW(sprite);
 		sprite_dl |= plane_prec |
 			     (drain_latency << DDL_SPRITE_SHIFT(sprite));
 	}
-- 
1.9.3