drm/radeon/kms: prefer legacy pll algo for tv-out

ntsc seems to work fine with either algo, some
pal TVs seem pickier.

Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=30832

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 3cd3234ba0af..10e41af6b026 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -957,7 +957,11 @@ static void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode
         /* adjust pixel clock as needed */
         adjusted_clock = atombios_adjust_pll(crtc, mode, pll, ss_enabled, &ss);
 
-        if (ASIC_IS_AVIVO(rdev))
+        if (radeon_encoder->active_device & (ATOM_DEVICE_TV_SUPPORT))
+                /* TV seems to prefer the legacy algo on some boards */
+                radeon_compute_pll_legacy(pll, adjusted_clock, &pll_clock, &fb_div, &frac_fb_div,
+                                          &ref_div, &post_div);
+        else if (ASIC_IS_AVIVO(rdev))
                 radeon_compute_pll_avivo(pll, adjusted_clock, &pll_clock, &fb_div, &frac_fb_div,
                                          &ref_div, &post_div);
         else