drm/radeon: use fixed PPL ref divider if needed

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

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 2f7cbb9..e6c3c54 100644 (file)
--- 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) {