diff --git a/arch/arm/mach-pxa/mainstone.c b/arch/arm/mach-pxa/mainstone.c
index 07892f4..fe74043 100644
--- a/arch/arm/mach-pxa/mainstone.c
+++ b/arch/arm/mach-pxa/mainstone.c
@@ -407,6 +407,12 @@
 	printk(KERN_NOTICE "Mainstone configured to boot from %s\n",
 	       mst_flash_data[0].name);
 
+	/* system bus arbiter setting
+	 * - Core_Park
+	 * - LCD_wt:DMA_wt:CORE_Wt = 2:3:4
+	 */
+	ARB_CNTRL = ARB_CORE_PARK | 0x234;
+
 	/*
 	 * On Mainstone, we route AC97_SYSCLK via GPIO45 to
 	 * the audio daughter card
diff --git a/include/asm-arm/arch-pxa/pxa-regs.h b/include/asm-arm/arch-pxa/pxa-regs.h
index a75a247..dae138b 100644
--- a/include/asm-arm/arch-pxa/pxa-regs.h
+++ b/include/asm-arm/arch-pxa/pxa-regs.h
@@ -2042,6 +2042,18 @@
 
 #ifdef CONFIG_PXA27x
 
+#define ARB_CNTRL	__REG(0x48000048)  /* Arbiter Control Register */
+
+#define ARB_DMA_SLV_PARK	(1<<31)	   /* Be parked with DMA slave when idle */
+#define ARB_CI_PARK		(1<<30)	   /* Be parked with Camera Interface when idle */
+#define ARB_EX_MEM_PARK 	(1<<29)	   /* Be parked with external MEMC when idle */
+#define ARB_INT_MEM_PARK	(1<<28)	   /* Be parked with internal MEMC when idle */
+#define ARB_USB_PARK		(1<<27)	   /* Be parked with USB when idle */
+#define ARB_LCD_PARK		(1<<26)	   /* Be parked with LCD when idle */
+#define ARB_DMA_PARK		(1<<25)	   /* Be parked with DMA when idle */
+#define ARB_CORE_PARK		(1<<24)	   /* Be parked with core when idle */
+#define ARB_LOCK_FLAG		(1<<23)	   /* Only Locking masters gain access to the bus */
+
 /*
  * Keypad
  */