egl/android: Restrict minimum triple buffering for android color_buffers

The patch restricts triple buffering as minimum at driver for android
color_buffers in order to fix onscreen performance hit for T-Rex and
Manhattan.

v2: Update min_buffer check condition (Tapani Pälli)
v3: further code cleanup (Eric Engestrom)

Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2332
Fixes: 0661c357c60 ("egl/android: Update color_buffers querying for buffer age")
Signed-off-by: Nataraj Deshpande <nataraj.deshpande@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3384>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3384>

diff --git a/src/egl/drivers/dri2/platform_android.c b/src/egl/drivers/dri2/platform_android.c
index 6ed0b416cf81266d79668f51ee9c6792e2190dac..d1b50a3fa7224bc9a84b0d7352c60e2a5bb4249a 100644 (file)
--- a/src/egl/drivers/dri2/platform_android.c
+++ b/src/egl/drivers/dri2/platform_android.c
@@ -375,6 +375,7 @@ droid_create_surface(_EGLDriver *drv, _EGLDisplay *disp, EGLint type,
    if (type == EGL_WINDOW_BIT) {
       int format;
       int buffer_count;
+      const int min_buffers = 3;
 
       if (window->common.magic != ANDROID_NATIVE_WINDOW_MAGIC) {
          _eglError(EGL_BAD_NATIVE_WINDOW, "droid_create_surface");
@@ -393,17 +394,20 @@ droid_create_surface(_EGLDriver *drv, _EGLDisplay *disp, EGLint type,
          _eglError(EGL_BAD_NATIVE_WINDOW, "droid_create_surface");
          goto cleanup_surface;
       }
-      if (native_window_set_buffer_count(window, buffer_count+1)) {
+
+      if (buffer_count < min_buffers)
+         buffer_count = min_buffers;
+      if (native_window_set_buffer_count(window, buffer_count)) {
          _eglError(EGL_BAD_NATIVE_WINDOW, "droid_create_surface");
          goto cleanup_surface;
       }
-      dri2_surf->color_buffers = calloc(buffer_count+1,
+      dri2_surf->color_buffers = calloc(buffer_count,
                                         sizeof(*dri2_surf->color_buffers));
       if (!dri2_surf->color_buffers) {
          _eglError(EGL_BAD_ALLOC, "droid_create_surface");
          goto cleanup_surface;
       }
-      dri2_surf->color_buffers_count = buffer_count+1;
+      dri2_surf->color_buffers_count = buffer_count;
 
       if (format != dri2_conf->base.NativeVisualID) {
          _eglLog(_EGL_WARNING, "Native format mismatch: 0x%x != 0x%x",