diff --git a/src/radeon_driver.c b/src/radeon_driver.c
index cc0b649..01666b9 100644
--- a/src/radeon_driver.c
+++ b/src/radeon_driver.c
@@ -2980,7 +2980,8 @@ RADEONInitBIOSRegisters(ScrnInfoPtr pScrn)
 	/* let the bios control the backlight */
 	save->bios_2_scratch &= ~ATOM_S2_VRI_BRIGHT_ENABLE;
 	/* tell the bios not to handle mode switching */
-	save->bios_6_scratch |= ATOM_S6_ACC_BLOCK_DISPLAY_SWITCH;
+	save->bios_6_scratch |= (ATOM_S6_ACC_BLOCK_DISPLAY_SWITCH |
+				 ATOM_S6_ACC_MODE);
 
 	if (info->ChipFamily >= CHIP_FAMILY_R600) {
 	    OUTREG(R600_BIOS_2_SCRATCH, save->bios_2_scratch);
diff --git a/src/radeon_output.c b/src/radeon_output.c
index 19ce36d..34e50b9 100644
--- a/src/radeon_output.c
+++ b/src/radeon_output.c
@@ -669,9 +669,9 @@ radeon_bios_output_lock(xf86OutputPtr output, Bool lock)
 
     if (info->IsAtomBios) {
 	if (lock) {
-	    save->bios_6_scratch |= (ATOM_S6_CRITICAL_STATE | ATOM_S6_ACC_MODE);
+	    save->bios_6_scratch |= (ATOM_S6_CRITICAL_STATE /*| ATOM_S6_ACC_MODE*/);
 	} else {
-	    save->bios_6_scratch &= ~(ATOM_S6_CRITICAL_STATE | ATOM_S6_ACC_MODE);
+	    save->bios_6_scratch &= ~(ATOM_S6_CRITICAL_STATE /*| ATOM_S6_ACC_MODE*/);
 	}
     } else {
 	if (lock) {