drm/i915: Workaround CHV pipe C cursor fail

[linux-drm-fsl-dcu.git] / drivers / gpu / drm / i915 / intel_display.c

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 13bc6d44293a09e46bd838e7691e1ad84a413b46..69e158789365cfd2ab390df1a0ca93ec83993280 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13728,6 +13728,7 @@ intel_check_cursor_plane(struct drm_plane *plane,
        struct drm_crtc *crtc = crtc_state->base.crtc;
        struct drm_framebuffer *fb = state->base.fb;
        struct drm_i915_gem_object *obj = intel_fb_obj(fb);
+       enum pipe pipe = to_intel_plane(plane)->pipe;
        unsigned stride;
        int ret;
 
@@ -13761,6 +13762,22 @@ intel_check_cursor_plane(struct drm_plane *plane,
                return -EINVAL;
        }
 
+       /*
+        * There's something wrong with the cursor on CHV pipe C.
+        * If it straddles the left edge of the screen then
+        * moving it away from the edge or disabling it often
+        * results in a pipe underrun, and often that can lead to
+        * dead pipe (constant underrun reported, and it scans
+        * out just a solid color). To recover from that, the
+        * display power well must be turned off and on again.
+        * Refuse the put the cursor into that compromised position.
+        */
+       if (IS_CHERRYVIEW(plane->dev) && pipe == PIPE_C &&
+           state->visible && state->base.crtc_x < 0) {
+               DRM_DEBUG_KMS("CHV cursor C not allowed to straddle the left screen edge\n");
+               return -EINVAL;
+       }
+
        return 0;
 }