REG_WRITE(D2VGA_CONTROL, 0);
REG_WRITE(D3VGA_CONTROL, 0);
REG_WRITE(D4VGA_CONTROL, 0);
+
+ /* HW Engineer's Notes:
+ * During switch from vga->extended, if we set the VGA_TEST_ENABLE and
+ * then hit the VGA_TEST_RENDER_START, then the DCHUBP timing gets updated correctly.
+ *
+ * Then vBIOS will have it poll for the VGA_TEST_RENDER_DONE and unset
+ * VGA_TEST_ENABLE, to leave it in the same state as before.
+ */
+ REG_UPDATE(VGA_TEST_CONTROL, VGA_TEST_ENABLE, 1);
+ REG_UPDATE(VGA_TEST_CONTROL, VGA_TEST_RENDER_START, 1);
}
static void dpp_pg_control(