diff --git a/src/i830_display.c b/src/i830_display.c
index 50fbc4d..a5fba27 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1123,7 +1123,8 @@ i830_update_dsparb(ScrnInfoPtr pScrn)
    xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(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 fifo_entries = 0, planea_entries = 0, planeb_entries = 0,
+       planec_entries = 0, i;
 
    if ((INREG(DSPACNTR) & DISPLAY_PLANE_ENABLE) &&
        (INREG(DSPBCNTR) & DISPLAY_PLANE_ENABLE))
@@ -1133,18 +1134,22 @@ i830_update_dsparb(ScrnInfoPtr pScrn)
   /*
     * FIFO entries will be split based on programmed modes
     */
-   if (IS_I965GM(pI830))
+   if (IS_I965GM(pI830)) {
        fifo_entries = 127;
-   else if (IS_I9XX(pI830))
+       planec_entries = 40;
+   } else if (IS_I9XX(pI830)) {
        fifo_entries = 95;
-   else if (IS_MOBILE(pI830)) {
+       planec_entries = 30;
+   } else if (IS_MOBILE(pI830)) {
        fifo_entries = 255;
+       planec_entries = 96;
    } else {
-	/* The 845/865 only have a AEND field.  Though the field size would
+       /* 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;
+       fifo_entries = 95;
+       planec_entries = 30;
    }
 
    for (i = 0; i < xf86_config->num_crtc; i++) {
@@ -1159,6 +1164,7 @@ i830_update_dsparb(ScrnInfoPtr pScrn)
       }
    }
 
+   fifo_entries -= planec_entries;
    planea_entries = fifo_entries * planea_hdisplay / total_hdisplay;
    planeb_entries = fifo_entries * planeb_hdisplay / total_hdisplay;