drm/radeon: use fixed PPL ref divider if needed

Signed-off-by: Christian König <christian.koenig@amd.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 2f7cbb901fb1..e6c3c5488259 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -880,7 +880,12 @@ void radeon_compute_pll_avivo(struct radeon_pll *pll,
                 ref_div_min = pll->reference_div;
         else
                 ref_div_min = pll->min_ref_div;
-        ref_div_max = pll->max_ref_div;
+
+        if (pll->flags & RADEON_PLL_USE_FRAC_FB_DIV &&
+            pll->flags & RADEON_PLL_USE_REF_DIV)
+                ref_div_max = pll->reference_div;
+        else
+                ref_div_max = pll->max_ref_div;
 
         /* determine allowed post divider range */
         if (pll->flags & RADEON_PLL_USE_POST_DIV) {