drm/i915: Calculate cursor watermark under non-SR state for Ironlake

The hardware team suggest that the "large buffer" method should be
used to calculate the cursor watermark under non-SR state as well,
which is to avoid the flicker when FBC is enabled on Ironlake.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

2 files changed, 56 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 1f741a6d0b12..d0ccfa0c72de 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2190,6 +2190,9 @@
 #define ILK_DISPLAY_FIFO        128
 #define ILK_DISPLAY_MAXWM       64
 #define ILK_DISPLAY_DFTWM       8
+#define ILK_CURSOR_FIFO         32
+#define ILK_CURSOR_MAXWM        16
+#define ILK_CURSOR_DFTWM        8
 
 #define ILK_DISPLAY_SR_FIFO     512
 #define ILK_DISPLAY_MAX_SRWM    0x1ff
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b580cd872b10..cca6ce80d464 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2590,6 +2590,14 @@ static struct intel_watermark_params ironlake_display_wm_info = {
         ILK_FIFO_LINE_SIZE
 };
 
+static struct intel_watermark_params ironlake_cursor_wm_info = {
+        ILK_CURSOR_FIFO,
+        ILK_CURSOR_MAXWM,
+        ILK_CURSOR_DFTWM,
+        2,
+        ILK_FIFO_LINE_SIZE
+};
+
 static struct intel_watermark_params ironlake_display_srwm_info = {
         ILK_DISPLAY_SR_FIFO,
         ILK_DISPLAY_MAX_SRWM,
@@ -3142,6 +3150,7 @@ static void i830_update_wm(struct drm_device *dev, int planea_clock, int unused,
 }
 
 #define ILK_LP0_PLANE_LATENCY           700
+#define ILK_LP0_CURSOR_LATENCY          1300
 
 static void ironlake_update_wm(struct drm_device *dev,  int planea_clock,
                        int planeb_clock, int sr_hdisplay, int sr_htotal,
@@ -3153,6 +3162,21 @@ static void ironlake_update_wm(struct drm_device *dev,  int planea_clock,
         unsigned long line_time_us;
         int sr_clock, entries_required;
         u32 reg_value;
+        int line_count;
+        int planea_htotal = 0, planeb_htotal = 0;
+        struct drm_crtc *crtc;
+        struct intel_crtc *intel_crtc;
+
+        /* Need htotal for all active display plane */
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                intel_crtc = to_intel_crtc(crtc);
+                if (crtc->enabled) {
+                        if (intel_crtc->plane == 0)
+                                planea_htotal = crtc->mode.htotal;
+                        else
+                                planeb_htotal = crtc->mode.htotal;
+                }
+        }
 
         /* Calculate and update the watermark for plane A */
         if (planea_clock) {
@@ -3166,7 +3190,20 @@ static void ironlake_update_wm(struct drm_device *dev,  int planea_clock,
                 if (planea_wm > (int)ironlake_display_wm_info.max_wm)
                         planea_wm = ironlake_display_wm_info.max_wm;
 
-                cursora_wm = 16;
+                /* Use the large buffer method to calculate cursor watermark */
+                line_time_us = (planea_htotal * 1000) / planea_clock;
+
+                /* Use ns/us then divide to preserve precision */
+                line_count = (ILK_LP0_CURSOR_LATENCY / line_time_us + 1000) / 1000;
+
+                /* calculate the cursor watermark for cursor A */
+                entries_required = line_count * 64 * pixel_size;
+                entries_required = DIV_ROUND_UP(entries_required,
+                                                ironlake_cursor_wm_info.cacheline_size);
+                cursora_wm = entries_required + ironlake_cursor_wm_info.guard_size;
+                if (cursora_wm > ironlake_cursor_wm_info.max_wm)
+                        cursora_wm = ironlake_cursor_wm_info.max_wm;
+
                 reg_value = I915_READ(WM0_PIPEA_ILK);
                 reg_value &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
                 reg_value |= (planea_wm << WM0_PIPE_PLANE_SHIFT) |
@@ -3187,7 +3224,20 @@ static void ironlake_update_wm(struct drm_device *dev,  int planea_clock,
                 if (planeb_wm > (int)ironlake_display_wm_info.max_wm)
                         planeb_wm = ironlake_display_wm_info.max_wm;
 
-                cursorb_wm = 16;
+                /* Use the large buffer method to calculate cursor watermark */
+                line_time_us = (planeb_htotal * 1000) / planeb_clock;
+
+                /* Use ns/us then divide to preserve precision */
+                line_count = (ILK_LP0_CURSOR_LATENCY / line_time_us + 1000) / 1000;
+
+                /* calculate the cursor watermark for cursor B */
+                entries_required = line_count * 64 * pixel_size;
+                entries_required = DIV_ROUND_UP(entries_required,
+                                                ironlake_cursor_wm_info.cacheline_size);
+                cursorb_wm = entries_required + ironlake_cursor_wm_info.guard_size;
+                if (cursorb_wm > ironlake_cursor_wm_info.max_wm)
+                        cursorb_wm = ironlake_cursor_wm_info.max_wm;
+
                 reg_value = I915_READ(WM0_PIPEB_ILK);
                 reg_value &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
                 reg_value |= (planeb_wm << WM0_PIPE_PLANE_SHIFT) |
@@ -3202,7 +3252,7 @@ static void ironlake_update_wm(struct drm_device *dev,  int planea_clock,
          * display plane is used.
          */
         if (!planea_clock || !planeb_clock) {
-                int line_count;
+
                 /* Read the self-refresh latency. The unit is 0.5us */
                 int ilk_sr_latency = I915_READ(MLTR_ILK) & ILK_SRLT_MASK;