Comment # 16 on bug 97260 from Alex Deucher

Does just reverting this chunk fix the issue?

@@ -1630,6 +1631,9 @@ int radeon_modeset_init(struct radeon_device *rdev)

        rdev->ddev->mode_config.funcs = &radeon_mode_funcs;

+       if (radeon_use_pflipirq == 2 && rdev->family >= CHIP_R600)
+               rdev->ddev->mode_config.async_page_flip = true;
+
        if (ASIC_IS_DCE5(rdev)) {
                rdev->ddev->mode_config.max_width = 16384;
                rdev->ddev->mode_config.max_height = 16384;