diff --git a/src/common.h b/src/common.h
index 57db6cb..f2ae502 100644
--- a/src/common.h
+++ b/src/common.h
@@ -374,6 +374,8 @@ extern int I810_DEBUG;
 /* chipsets require status page in non stolen memory */
 #define HWS_NEED_NONSTOLEN(pI810) (IS_GM45(pI810) || IS_G4X(pI810))
 #define SUPPORTS_INTEGRATED_HDMI(pI810) (IS_GM45(pI810) || IS_G4X(pI810))
+/* dsparb controlled by hw only */
+#define DSPARB_HWCONTROL(pI810) (IS_G4X(pI810) || IS_GM45(pI810))
 
 #define GTT_PAGE_SIZE			KB(4)
 #define ROUND_TO(x, y)			(((x) + (y) - 1) / (y) * (y))
diff --git a/src/i830_display.c b/src/i830_display.c
index 6176447..2e1de41 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1510,7 +1510,8 @@ i830_crtc_mode_set(xf86CrtcPtr crtc, DisplayModePtr mode,
     
     i830WaitForVblank(pScrn);
 
-    i830_update_dsparb(pScrn);
+    if (!DSPARB_HWCONTROL(pI830))
+	i830_update_dsparb(pScrn);
 
     /* Clear any FIFO underrun status that may have occurred normally */
     OUTREG(pipestat_reg, INREG(pipestat_reg) | FIFO_UNDERRUN);
diff --git a/src/i830_driver.c b/src/i830_driver.c
index 4bb9b81..f5aa114 100644
--- a/src/i830_driver.c
+++ b/src/i830_driver.c
@@ -2018,7 +2018,8 @@ SaveHWState(ScrnInfoPtr pScrn)
    }
 
    /* Save video mode information for native mode-setting. */
-   pI830->saveDSPARB = INREG(DSPARB);
+   if (!DSPARB_HWCONTROL(pI830))
+       pI830->saveDSPARB = INREG(DSPARB);
 
    pI830->saveDSPACNTR = INREG(DSPACNTR);
    pI830->savePIPEACONF = INREG(PIPEACONF);
@@ -2161,7 +2162,8 @@ RestoreHWState(ScrnInfoPtr pScrn)
    if (!IS_I830(pI830) && !IS_845G(pI830))
      OUTREG(PFIT_CONTROL, pI830->savePFIT_CONTROL);
 
-   OUTREG(DSPARB, pI830->saveDSPARB);
+   if (!DSPARB_HWCONTROL(pI830))
+       OUTREG(DSPARB, pI830->saveDSPARB);
 
    OUTREG(DSPCLK_GATE_D, pI830->saveDSPCLK_GATE_D);
    OUTREG(RENCLK_GATE_D1, pI830->saveRENCLK_GATE_D1);
@@ -2512,7 +2514,7 @@ I830BlockHandler(int i,
      * (except for mode setting, where it may occur naturally).
      * Check & ack the condition.
      */
-    if (pScrn->vtSema) {
+    if (pScrn->vtSema && !DSPARB_HWCONTROL(pI830)) {
 	if (xf86_config->crtc[0]->enabled &&
 		(INREG(PIPEASTAT) & FIFO_UNDERRUN)) {
 	    xf86DrvMsg(pScrn->scrnIndex, X_ERROR, "underrun on pipe A!\n");