drm/radeon/dce32+: use fractional fb dividers for high clocks

commit a02dc74b317d78298cb0587b9b1f6f741fd5c139 upstream.

Fixes flickering with some high res montiors.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[bwh: Backported to 3.2: use pll->flags instead of radeon_crtc->pll_flags]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index ebbfbd2017396ae674b59e51e1d9e35c1cbd817b..77dc799215a5e4cc325211beb4c55ede803d561e 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -573,6 +573,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
                /* use frac fb div on APUs */
                if (ASIC_IS_DCE41(rdev) || ASIC_IS_DCE61(rdev))
                        pll->flags |= RADEON_PLL_USE_FRAC_FB_DIV;
+               if (ASIC_IS_DCE32(rdev) && mode->clock > 165000)
+                       pll->flags |= RADEON_PLL_USE_FRAC_FB_DIV;
        } else {
                pll->flags |= RADEON_PLL_LEGACY;