diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 9fbabaa..b3e5e75 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -673,9 +673,14 @@ union set_pixel_clock {
 	PIXEL_CLOCK_PARAMETERS_V2 v2;
 	PIXEL_CLOCK_PARAMETERS_V3 v3;
 	PIXEL_CLOCK_PARAMETERS_V5 v5;
+	PIXEL_CLOCK_PARAMETERS_V6 v6;
 };
 
-static void atombios_crtc_set_dcpll(struct drm_crtc *crtc)
+/* on DCE5, make sure the voltage is high enough to support the
+ * required disp clk.
+ */
+static void atombios_crtc_set_dcpll(struct drm_crtc *crtc,
+				    u32 dispclk)
 {
 	struct drm_device *dev = crtc->dev;
 	struct radeon_device *rdev = dev->dev_private;
@@ -698,9 +703,16 @@ static void atombios_crtc_set_dcpll(struct drm_crtc *crtc)
 			 * SetPixelClock provides the dividers
 			 */
 			args.v5.ucCRTC = ATOM_CRTC_INVALID;
-			args.v5.usPixelClock = rdev->clock.default_dispclk;
+			args.v5.usPixelClock = dispclk;
 			args.v5.ucPpll = ATOM_DCPLL;
 			break;
+		case 6:
+			/* if the default dcpll clock is specified,
+			 * SetPixelClock provides the dividers
+			 */
+			args.v6.ulDispEngClkFreq = dispclk;
+			args.v6.ucPpll = ATOM_DCPLL;
+			break;
 		default:
 			DRM_ERROR("Unknown table version %d %d\n", frev, crev);
 			return;
@@ -784,6 +796,18 @@ static void atombios_crtc_program_pll(struct drm_crtc *crtc,
 			args.v5.ucEncoderMode = encoder_mode;
 			args.v5.ucPpll = pll_id;
 			break;
+		case 6:
+			args.v6.ulCrtcPclkFreq.ucCRTC = crtc_id;
+			args.v6.ulCrtcPclkFreq.ulPixelClock = cpu_to_le32(clock / 10);
+			args.v6.ucRefDiv = ref_div;
+			args.v6.usFbDiv = cpu_to_le16(fb_div);
+			args.v6.ulFbDivDecFrac = cpu_to_le32(frac_fb_div * 100000);
+			args.v6.ucPostDiv = post_div;
+			args.v6.ucMiscInfo = 0; /* HDMI depth, etc. */
+			args.v6.ucTransmitterID = encoder_id;
+			args.v6.ucEncoderMode = encoder_mode;
+			args.v6.ucPpll = pll_id;
+			break;
 		default:
 			DRM_ERROR("Unknown table version %d %d\n", frev, crev);
 			return;
@@ -1377,7 +1401,8 @@ int atombios_crtc_mode_set(struct drm_crtc *crtc,
 								   rdev->clock.default_dispclk);
 		if (ss_enabled)
 			atombios_crtc_program_ss(crtc, ATOM_DISABLE, ATOM_DCPLL, &ss);
-		atombios_crtc_set_dcpll(crtc);
+		/* XXX: DCE5, make sure voltage, dispclk is high enough */
+		atombios_crtc_set_dcpll(crtc, rdev->clock.default_dispclk);
 		if (ss_enabled)
 			atombios_crtc_program_ss(crtc, ATOM_ENABLE, ATOM_DCPLL, &ss);
 	}
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index e4f7e3e..11573d0 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -1086,6 +1086,7 @@ union firmware_info {
 	ATOM_FIRMWARE_INFO_V1_3 info_13;
 	ATOM_FIRMWARE_INFO_V1_4 info_14;
 	ATOM_FIRMWARE_INFO_V2_1 info_21;
+	ATOM_FIRMWARE_INFO_V2_2 info_22;
 };
 
 bool radeon_atom_get_clock_info(struct drm_device *dev)
@@ -1160,8 +1161,12 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		*p2pll = *p1pll;
 
 		/* system clock */
-		spll->reference_freq =
-		    le16_to_cpu(firmware_info->info.usReferenceClock);
+		if (ASIC_IS_DCE4(rdev))
+			spll->reference_freq =
+				le16_to_cpu(firmware_info->info_21.usCoreReferenceClock);
+		else
+			spll->reference_freq =
+				le16_to_cpu(firmware_info->info.usReferenceClock);
 		spll->reference_div = 0;
 
 		spll->pll_out_min =
@@ -1183,8 +1188,12 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		    le16_to_cpu(firmware_info->info.usMaxEngineClockPLL_Input);
 
 		/* memory clock */
-		mpll->reference_freq =
-		    le16_to_cpu(firmware_info->info.usReferenceClock);
+		if (ASIC_IS_DCE4(rdev))
+			mpll->reference_freq =
+				le16_to_cpu(firmware_info->info_21.usMemoryReferenceClock);
+		else
+			mpll->reference_freq =
+				le16_to_cpu(firmware_info->info.usReferenceClock);
 		mpll->reference_div = 0;
 
 		mpll->pll_out_min =
@@ -1213,8 +1222,12 @@ bool radeon_atom_get_clock_info(struct drm_device *dev)
 		if (ASIC_IS_DCE4(rdev)) {
 			rdev->clock.default_dispclk =
 				le32_to_cpu(firmware_info->info_21.ulDefaultDispEngineClkFreq);
-			if (rdev->clock.default_dispclk == 0)
-				rdev->clock.default_dispclk = 60000; /* 600 Mhz */
+			if (rdev->clock.default_dispclk == 0) {
+				if (ASIC_IS_DCE5(rdev))
+					rdev->clock.default_dispclk = 54000; /* 540 Mhz */
+				else
+					rdev->clock.default_dispclk = 60000; /* 600 Mhz */
+			}
 			rdev->clock.dp_extclk =
 				le16_to_cpu(firmware_info->info_21.usUniphyDPModeExtClkFreq);
 		}
