drm/i915: Clear self-refresh watermarks when disabled

If we elect to disable self-refresh as they require too many FIFO
entries, clear the values prior to writing them into the registers. If
they are too large they may occupy more bits than available and so
corrupt neighbouring WM values.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index cdd70e654af5a2812c473027a48f7382640fee62..bfc46529f6df3f709299d3c8802497591021e057 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -1303,7 +1303,6 @@ static void valleyview_update_wm(struct drm_device *dev)
                            &planeb_wm, &cursorb_wm))
                enabled |= 2;
 
-       plane_sr = cursor_sr = 0;
        if (single_plane_enabled(enabled) &&
            g4x_compute_srwm(dev, ffs(enabled) - 1,
                             sr_latency_ns,
@@ -1314,11 +1313,13 @@ static void valleyview_update_wm(struct drm_device *dev)
                             2*sr_latency_ns,
                             &valleyview_wm_info,
                             &valleyview_cursor_wm_info,
-                            &ignore_plane_sr, &cursor_sr))
+                            &ignore_plane_sr, &cursor_sr)) {
                I915_WRITE(FW_BLC_SELF_VLV, FW_CSPWRDWNEN);
-       else
+       } else {
                I915_WRITE(FW_BLC_SELF_VLV,
                           I915_READ(FW_BLC_SELF_VLV) & ~FW_CSPWRDWNEN);
+               plane_sr = cursor_sr = 0;
+       }
 
        DRM_DEBUG_KMS("Setting FIFO watermarks - A: plane=%d, cursor=%d, B: plane=%d, cursor=%d, SR: plane=%d, cursor=%d\n",
                      planea_wm, cursora_wm,
@@ -1358,17 +1359,18 @@ static void g4x_update_wm(struct drm_device *dev)
                            &planeb_wm, &cursorb_wm))
                enabled |= 2;
 
-       plane_sr = cursor_sr = 0;
        if (single_plane_enabled(enabled) &&
            g4x_compute_srwm(dev, ffs(enabled) - 1,
                             sr_latency_ns,
                             &g4x_wm_info,
                             &g4x_cursor_wm_info,
-                            &plane_sr, &cursor_sr))
+                            &plane_sr, &cursor_sr)) {
                I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
-       else
+       } else {
                I915_WRITE(FW_BLC_SELF,
                           I915_READ(FW_BLC_SELF) & ~FW_BLC_SELF_EN);
+               plane_sr = cursor_sr = 0;
+       }
 
        DRM_DEBUG_KMS("Setting FIFO watermarks - A: plane=%d, cursor=%d, B: plane=%d, cursor=%d, SR: plane=%d, cursor=%d\n",
                      planea_wm, cursora_wm,