drm/radeon/kms: leave certain CP int bits enabled

These bits are used for internal communication and should
be left enabled.  This may fix s/r issues on some systems.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/evergreen.c

@@ -1521,7 +1521,7 @@ void evergreen_disable_interrupt_state(struct radeon_device *rdev)
 {
 	u32 tmp;
 
-	WREG32(CP_INT_CNTL, 0);
+	WREG32(CP_INT_CNTL, CNTX_BUSY_INT_ENABLE | CNTX_EMPTY_INT_ENABLE);
 	WREG32(GRBM_INT_CNTL, 0);
 	WREG32(INT_MASK + EVERGREEN_CRTC0_REGISTER_OFFSET, 0);
 	WREG32(INT_MASK + EVERGREEN_CRTC1_REGISTER_OFFSET, 0);

drivers/gpu/drm/radeon/r600.c

@@ -2912,7 +2912,7 @@ static void r600_disable_interrupt_state(struct radeon_device *rdev)
 {
 	u32 tmp;
 
-	WREG32(CP_INT_CNTL, 0);
+	WREG32(CP_INT_CNTL, CNTX_BUSY_INT_ENABLE | CNTX_EMPTY_INT_ENABLE);
 	WREG32(GRBM_INT_CNTL, 0);
 	WREG32(DxMODE_INT_MASK, 0);
 	if (ASIC_IS_DCE3(rdev)) {