diff options
| -rw-r--r-- | drivers/gpu/drm/radeon/radeon_display.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c index 14bd701e316c..9ff0e2f1be6a 100644 --- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -830,14 +830,14 @@ static void avivo_reduce_ratio(unsigned *nom, unsigned *den, /* make sure nominator is large enough */ if (*nom < nom_min) { - tmp = (nom_min + *nom - 1) / *nom; + tmp = DIV_ROUND_UP(nom_min, *nom); *nom *= tmp; *den *= tmp; } /* make sure the denominator is large enough */ if (*den < den_min) { - tmp = (den_min + *den - 1) / *den; + tmp = DIV_ROUND_UP(den_min, *den); *nom *= tmp; *den *= tmp; } @@ -997,6 +997,16 @@ void radeon_compute_pll_avivo(struct radeon_pll *pll, /* this also makes sure that the reference divider is large enough */ avivo_reduce_ratio(&fb_div, &ref_div, fb_div_min, ref_div_min); + /* avoid high jitter with small fractional dividers */ + if (pll->flags & RADEON_PLL_USE_FRAC_FB_DIV && (fb_div % 10)) { + fb_div_min = max(fb_div_min, (9 - (fb_div % 10)) * 20 + 60); + if (fb_div < fb_div_min) { + unsigned tmp = DIV_ROUND_UP(fb_div_min, fb_div); + fb_div *= tmp; + ref_div *= tmp; + } + } + /* and finally save the result */ if (pll->flags & RADEON_PLL_USE_FRAC_FB_DIV) { *fb_div_p = fb_div / 10; |