drm/i915: properly mask and or watermark values for sprites

Now that we're using the sprite WM fields, we need to take care not to
clobber them in the main update_wm functions.  While we're at it, make
sure we mask out the old sprite wm value before or'ing in the new one
when the sprite wm is updated.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4247a7b1823..ec31350337d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4548,6 +4548,7 @@ void sandybridge_update_wm(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
         int latency = SNB_READ_WM0_LATENCY() * 100;     /* In unit 0.1us */
+        u32 val;
         int fbc_wm, plane_wm, cursor_wm;
         unsigned int enabled;
 
@@ -4556,8 +4557,10 @@ void sandybridge_update_wm(struct drm_device *dev)
                             &sandybridge_display_wm_info, latency,
                             &sandybridge_cursor_wm_info, latency,
                             &plane_wm, &cursor_wm)) {
-                I915_WRITE(WM0_PIPEA_ILK,
-                           (plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm);
+                val = I915_READ(WM0_PIPEA_ILK);
+                val &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
+                I915_WRITE(WM0_PIPEA_ILK, val |
+                           ((plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm));
                 DRM_DEBUG_KMS("FIFO watermarks For pipe A -"
                               " plane %d, " "cursor: %d\n",
                               plane_wm, cursor_wm);
@@ -4568,8 +4571,10 @@ void sandybridge_update_wm(struct drm_device *dev)
                             &sandybridge_display_wm_info, latency,
                             &sandybridge_cursor_wm_info, latency,
                             &plane_wm, &cursor_wm)) {
-                I915_WRITE(WM0_PIPEB_ILK,
-                           (plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm);
+                val = I915_READ(WM0_PIPEB_ILK);
+                val &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
+                I915_WRITE(WM0_PIPEB_ILK, val |
+                           ((plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm));
                 DRM_DEBUG_KMS("FIFO watermarks For pipe B -"
                               " plane %d, cursor: %d\n",
                               plane_wm, cursor_wm);
@@ -4582,8 +4587,10 @@ void sandybridge_update_wm(struct drm_device *dev)
                             &sandybridge_display_wm_info, latency,
                             &sandybridge_cursor_wm_info, latency,
                             &plane_wm, &cursor_wm)) {
-                I915_WRITE(WM0_PIPEC_IVB,
-                           (plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm);
+                val = I915_READ(WM0_PIPEC_IVB);
+                val &= ~(WM0_PIPE_PLANE_MASK | WM0_PIPE_CURSOR_MASK);
+                I915_WRITE(WM0_PIPEC_IVB, val |
+                           ((plane_wm << WM0_PIPE_PLANE_SHIFT) | cursor_wm));
                 DRM_DEBUG_KMS("FIFO watermarks For pipe C -"
                               " plane %d, cursor: %d\n",
                               plane_wm, cursor_wm);
@@ -4727,6 +4734,7 @@ static void sandybridge_update_sprite_wm(struct drm_device *dev, int pipe,
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
         int latency = SNB_READ_WM0_LATENCY() * 100;     /* In unit 0.1us */
+        u32 val;
         int sprite_wm, reg;
         int ret;
 
@@ -4753,7 +4761,9 @@ static void sandybridge_update_sprite_wm(struct drm_device *dev, int pipe,
                 return;
         }
 
-        I915_WRITE(reg, I915_READ(reg) | (sprite_wm << WM0_PIPE_SPRITE_SHIFT));
+        val = I915_READ(reg);
+        val &= ~WM0_PIPE_SPRITE_MASK;
+        I915_WRITE(reg, val | (sprite_wm << WM0_PIPE_SPRITE_SHIFT));
         DRM_DEBUG_KMS("sprite watermarks For pipe %d - %d\n", pipe, sprite_wm);