drm/gma500/psb: Unpin framebuffer on crtc disable

The framebuffer needs to be unpinned in the crtc->disable callback
because of previous pinning in psb_intel_pipe_set_base(). This will fix
a memory leak where the framebuffer was released but not unpinned
properly. This patch only affects Poulsbo.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=889511
Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=812113
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>

drivers/gpu/drm/gma500/psb_intel_display.c

@@ -1150,13 +1150,27 @@ static void psb_intel_crtc_destroy(struct drm_crtc *crtc)
 	kfree(psb_intel_crtc);
 }
 
+static void psb_intel_crtc_disable(struct drm_crtc *crtc)
+{
+	struct gtt_range *gt;
+	struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+	crtc_funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
+
+	if (crtc->fb) {
+		gt = to_psb_fb(crtc->fb)->gtt;
+		psb_gtt_unpin(gt);
+	}
+}
+
 const struct drm_crtc_helper_funcs psb_intel_helper_funcs = {
 	.dpms = psb_intel_crtc_dpms,
 	.mode_fixup = psb_intel_crtc_mode_fixup,
 	.mode_set = psb_intel_crtc_mode_set,
 	.mode_set_base = psb_intel_pipe_set_base,
 	.prepare = psb_intel_crtc_prepare,
 	.commit = psb_intel_crtc_commit,
+	.disable = psb_intel_crtc_disable,
 };
 
 const struct drm_crtc_funcs psb_intel_crtc_funcs = {