diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index ab37717a5d39..5aa299527317 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -2365,11 +2365,10 @@ void r100_mc_init(struct radeon_device *rdev)
  */
 void r100_pll_errata_after_index(struct radeon_device *rdev)
 {
-	if (!(rdev->pll_errata & CHIP_ERRATA_PLL_DUMMYREADS)) {
-		return;
+	if (rdev->pll_errata & CHIP_ERRATA_PLL_DUMMYREADS) {
+		(void)RREG32(RADEON_CLOCK_CNTL_DATA);
+		(void)RREG32(RADEON_CRTC_GEN_CNTL);
 	}
-	(void)RREG32(RADEON_CLOCK_CNTL_DATA);
-	(void)RREG32(RADEON_CRTC_GEN_CNTL);
 }
 
 static void r100_pll_errata_after_data(struct radeon_device *rdev)
diff --git a/drivers/gpu/drm/radeon/radeon_combios.c b/drivers/gpu/drm/radeon/radeon_combios.c
index d1c1d8dd93ce..3426dd22aa08 100644
--- a/drivers/gpu/drm/radeon/radeon_combios.c
+++ b/drivers/gpu/drm/radeon/radeon_combios.c
@@ -2941,9 +2941,8 @@ static void combios_write_ram_size(struct drm_device *dev)
 		if (rev < 3) {
 			mem_cntl = RBIOS32(offset + 1);
 			mem_size = RBIOS16(offset + 5);
-			if (((rdev->flags & RADEON_FAMILY_MASK) < CHIP_R200) &&
-			    ((dev->pdev->device != 0x515e)
-			     && (dev->pdev->device != 0x5969)))
+			if ((rdev->family < CHIP_R200) &&
+			    !ASIC_IS_RN50(rdev))
 				WREG32(RADEON_MEM_CNTL, mem_cntl);
 		}
 	}
@@ -2954,10 +2953,8 @@ static void combios_write_ram_size(struct drm_device *dev)
 		if (offset) {
 			rev = RBIOS8(offset - 1);
 			if (rev < 1) {
-				if (((rdev->flags & RADEON_FAMILY_MASK) <
-				     CHIP_R200)
-				    && ((dev->pdev->device != 0x515e)
-					&& (dev->pdev->device != 0x5969))) {
+				if ((rdev->family < CHIP_R200)
+				    && !ASIC_IS_RN50(rdev)) {
 					int ram = 0;
 					int mem_addr_mapping = 0;