hwc: add tolerance to video aspect ratio changes

Slight changes in the aspect ratio of the external layer occur
when the layer is resized on screen due to rounding errors.
Add tolerance, so we do not reconfigure HDMI due to these slight
changes.

Change-Id: I4b1b4c5dfb80ebbd83e26eb78dd86269b756307c

1 files changed, 2 insertions, 1 deletions

diff --git a/hwc/hwc.c b/hwc/hwc.c
index 01d7119f..e2762b73 100644
--- a/hwc/hwc.c
+++ b/hwc/hwc.c
@@ -1113,7 +1113,8 @@ static int omap4_hwc_prepare(struct hwc_composer_device *dev, hwc_layer_list_t*
                 /* adjust hdmi mode based on resolution */
                 if (xres != hwc_dev->ext.last_xres_used ||
                     yres != hwc_dev->ext.last_yres_used ||
-                    xpy != hwc_dev->ext.last_xpy) {
+                    xpy < hwc_dev->ext.last_xpy * (1.f - ASPECT_RATIO_TOLERANCE) ||
+                    xpy * (1.f - ASPECT_RATIO_TOLERANCE) > hwc_dev->ext.last_xpy) {
                     LOGD("set up HDMI for %d*%d\n", xres, yres);
                     if (omap4_hwc_set_best_hdmi_mode(hwc_dev, xres, yres, xpy)) {
                         o->cfg.enabled = 0;