diff --git a/src/i830_dri.c b/src/i830_dri.c
index 2203c9e..b24d082 100644
--- a/src/i830_dri.c
+++ b/src/i830_dri.c
@@ -1684,6 +1684,8 @@ I830DRISetVBlankInterrupt (ScrnInfoPtr pScrn, Bool on)
     xf86CrtcConfigPtr   xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
     drmI830VBlankPipe pipe;
 
+ErrorF("%s: pI830->directRenderingEnabled=%d pI830->drmMinor=%d xf86_config->num_crtc=%d xf86_config->crtc[1]->enabled=%d\n", __func__,
+       pI830->directRenderingEnabled, pI830->drmMinor, xf86_config->num_crtc, xf86_config->crtc[1]->enabled);
     if (pI830->directRenderingEnabled && pI830->drmMinor >= 5) {
 	if (on) {
 	    if (xf86_config->num_crtc > 1 && xf86_config->crtc[1]->enabled)