Commit e65cf94a authored by Christian König's avatar Christian König Committed by Greg Kroah-Hartman

drm/radeon: prefer lower reference dividers

commit 2e26ccb1 upstream.

Instead of the closest reference divider prefer the lowest,
this fixes flickering issues on HP Compaq nx9420.

Bugs: https://bugs.freedesktop.org/show_bug.cgi?id=108514Suggested-by: default avatarPaul Dufresne <dufresnep@gmail.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Acked-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ad4cfd49
......@@ -922,12 +922,12 @@ static void avivo_get_fb_ref_div(unsigned nom, unsigned den, unsigned post_div,
ref_div_max = max(min(100 / post_div, ref_div_max), 1u);
/* get matching reference and feedback divider */
*ref_div = min(max(DIV_ROUND_CLOSEST(den, post_div), 1u), ref_div_max);
*ref_div = min(max(den/post_div, 1u), ref_div_max);
*fb_div = DIV_ROUND_CLOSEST(nom * *ref_div * post_div, den);
/* limit fb divider to its maximum */
if (*fb_div > fb_div_max) {
*ref_div = DIV_ROUND_CLOSEST(*ref_div * fb_div_max, *fb_div);
*ref_div = (*ref_div * fb_div_max)/(*fb_div);
*fb_div = fb_div_max;
}
}
......
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