1 files changed, 21 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_clocks.c b/drivers/gpu/drm/radeon/radeon_clocks.c
index a81354167621..b062109efbee 100644
--- a/drivers/gpu/drm/radeon/radeon_clocks.c
+++ b/drivers/gpu/drm/radeon/radeon_clocks.c
@@ -44,6 +44,10 @@ uint32_t radeon_legacy_get_engine_clock(struct radeon_device *rdev)
 
         ref_div =
             RREG32_PLL(RADEON_M_SPLL_REF_FB_DIV) & RADEON_M_SPLL_REF_DIV_MASK;
+
+        if (ref_div == 0)
+                return 0;
+
         sclk = fb_div / ref_div;
 
         post_div = RREG32_PLL(RADEON_SCLK_CNTL) & RADEON_SCLK_SRC_SEL_MASK;
@@ -70,6 +74,10 @@ static uint32_t radeon_legacy_get_memory_clock(struct radeon_device *rdev)
 
         ref_div =
             RREG32_PLL(RADEON_M_SPLL_REF_FB_DIV) & RADEON_M_SPLL_REF_DIV_MASK;
+
+        if (ref_div == 0)
+                return 0;
+
         mclk = fb_div / ref_div;
 
         post_div = RREG32_PLL(RADEON_MCLK_CNTL) & 0x7;
@@ -98,8 +106,19 @@ void radeon_get_clock_info(struct drm_device *dev)
                 ret = radeon_combios_get_clock_info(dev);
 
         if (ret) {
-                if (p1pll->reference_div < 2)
-                        p1pll->reference_div = 12;
+                if (p1pll->reference_div < 2) {
+                        if (!ASIC_IS_AVIVO(rdev)) {
+                                u32 tmp = RREG32_PLL(RADEON_PPLL_REF_DIV);
+                                if (ASIC_IS_R300(rdev))
+                                        p1pll->reference_div =
+                                                (tmp & R300_PPLL_REF_DIV_ACC_MASK) >> R300_PPLL_REF_DIV_ACC_SHIFT;
+                                else
+                                        p1pll->reference_div = tmp & RADEON_PPLL_REF_DIV_MASK;
+                                if (p1pll->reference_div < 2)
+                                        p1pll->reference_div = 12;
+                        } else
+                                p1pll->reference_div = 12;
+                }
                 if (p2pll->reference_div < 2)
                         p2pll->reference_div = 12;
                 if (rdev->family < CHIP_RS600) {