drm/radeon/dpm: fix fallback for empty UVD clocks

Some older 6xx-7xx boards didn't always fill in the
UVD clocks properly in the UVD power states.  This
leads to the driver trying to set a 0 clock which
results in slow or broken UVD playback.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=69120

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/radeon/rs780_dpm.c

@@ -726,14 +726,18 @@ static void rs780_parse_pplib_non_clock_info(struct radeon_device *rdev,
 	if (ATOM_PPLIB_NONCLOCKINFO_VER1 < table_rev) {
 		rps->vclk = le32_to_cpu(non_clock_info->ulVCLK);
 		rps->dclk = le32_to_cpu(non_clock_info->ulDCLK);
-	} else if (r600_is_uvd_state(rps->class, rps->class2)) {
-		rps->vclk = RS780_DEFAULT_VCLK_FREQ;
-		rps->dclk = RS780_DEFAULT_DCLK_FREQ;
 	} else {
 		rps->vclk = 0;
 		rps->dclk = 0;
 	}
 
+	if (r600_is_uvd_state(rps->class, rps->class2)) {
+		if ((rps->vclk == 0) || (rps->dclk == 0)) {
+			rps->vclk = RS780_DEFAULT_VCLK_FREQ;
+			rps->dclk = RS780_DEFAULT_DCLK_FREQ;
+		}
+	}
+
 	if (rps->class & ATOM_PPLIB_CLASSIFICATION_BOOT)
 		rdev->pm.dpm.boot_ps = rps;
 	if (rps->class & ATOM_PPLIB_CLASSIFICATION_UVDSTATE)

drivers/gpu/drm/radeon/rv770_dpm.c

@@ -2147,14 +2147,18 @@ static void rv7xx_parse_pplib_non_clock_info(struct radeon_device *rdev,
 	if (ATOM_PPLIB_NONCLOCKINFO_VER1 < table_rev) {
 		rps->vclk = le32_to_cpu(non_clock_info->ulVCLK);
 		rps->dclk = le32_to_cpu(non_clock_info->ulDCLK);
-	} else if (r600_is_uvd_state(rps->class, rps->class2)) {
-		rps->vclk = RV770_DEFAULT_VCLK_FREQ;
-		rps->dclk = RV770_DEFAULT_DCLK_FREQ;
 	} else {
 		rps->vclk = 0;
 		rps->dclk = 0;
 	}
 
+	if (r600_is_uvd_state(rps->class, rps->class2)) {
+		if ((rps->vclk == 0) || (rps->dclk == 0)) {
+			rps->vclk = RV770_DEFAULT_VCLK_FREQ;
+			rps->dclk = RV770_DEFAULT_DCLK_FREQ;
+		}
+	}
+
 	if (rps->class & ATOM_PPLIB_CLASSIFICATION_BOOT)
 		rdev->pm.dpm.boot_ps = rps;
 	if (rps->class & ATOM_PPLIB_CLASSIFICATION_UVDSTATE)