diff --git a/src/i830_display.c b/src/i830_display.c
index f81847b..8a1bbd7 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1104,6 +1104,7 @@ i830_update_dsparb(ScrnInfoPtr pScrn)
    I830Ptr pI830 = I830PTR(pScrn);
    int total_hdisplay = 0, planea_hdisplay = 0, planeb_hdisplay = 0;
    int fifo_entries = 0, planea_entries = 0, planeb_entries = 0, i;
+   int planec_entries = 37;
 
    if ((INREG(DSPACNTR) & DISPLAY_PLANE_ENABLE) &&
        (INREG(DSPBCNTR) & DISPLAY_PLANE_ENABLE))
@@ -1119,14 +1120,18 @@ i830_update_dsparb(ScrnInfoPtr pScrn)
        fifo_entries = 95;
    else if (IS_MOBILE(pI830)) {
        fifo_entries = 255;
+       planec_entries = 0;
    } else {
 	/* The 845/865 only have a AEND field.  Though the field size would
 	* allow 128 entries, the 865 rendered the cursor wrong then.
 	* The BIOS set it up for 96.
 	*/
 	fifo_entries = 95;
+	planec_entries = 0;
    }
 
+   fifo_entries -= planec_entries;
+
    for (i = 0; i < xf86_config->num_crtc; i++) {
       xf86CrtcPtr crtc = xf86_config->crtc[i];
       I830CrtcPrivatePtr intel_crtc = crtc->driver_private;