Messages in this thread | | | Subject | Re: [PATCH] drm/radeon: Prefer lower feedback dividers | From | Christian König <> | Date | Thu, 27 Aug 2020 13:18:33 +0200 |
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Am 25.08.20 um 19:33 schrieb Kai-Heng Feng: > Commit 2e26ccb119bd ("drm/radeon: prefer lower reference dividers") > fixed screen flicker for HP Compaq nx9420 but breaks other laptops like > Asus X50SL. > > Turns out we also need to favor lower feedback dividers.
Mhm, let's hope that this works out for all others as well :)
> > Users confirmed this change fixes the regression and doesn't regress the > original fix. > > Fixes: 2e26ccb119bd ("drm/radeon: prefer lower reference dividers") > BugLink: https://bugs.launchpad.net/bugs/1791312 > BugLink: https://bugs.launchpad.net/bugs/1861554 > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
> --- > drivers/gpu/drm/radeon/radeon_display.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c > index e0ae911ef427..7b69d6dfe44a 100644 > --- a/drivers/gpu/drm/radeon/radeon_display.c > +++ b/drivers/gpu/drm/radeon/radeon_display.c > @@ -933,7 +933,7 @@ static void avivo_get_fb_ref_div(unsigned nom, unsigned den, unsigned post_div, > > /* get matching reference and feedback divider */ > *ref_div = min(max(den/post_div, 1u), ref_div_max); > - *fb_div = DIV_ROUND_CLOSEST(nom * *ref_div * post_div, den); > + *fb_div = max(nom * *ref_div * post_div / den, 1u); > > /* limit fb divider to its maximum */ > if (*fb_div > fb_div_max) {
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