drm/radeon: disable pll sharing for DP on DCE4.1

Causes display problems.  We had already disabled
sharing for non-DP displays.

Based on a patch from:
Niels Ole Salscheider <niels_ole@salscheider-online.de>

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=58121

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 0d19f4f..daa4dd3 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -1774,6 +1774,20 @@ static int radeon_atom_pick_pll(struct drm_crtc *crtc)
                        return ATOM_PPLL1;
                DRM_ERROR("unable to allocate a PPLL\n");
                return ATOM_PPLL_INVALID;
+       } else if (ASIC_IS_DCE41(rdev)) {
+               /* Don't share PLLs on DCE4.1 chips */
+               if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(radeon_crtc->encoder))) {
+                       if (rdev->clock.dp_extclk)
+                               /* skip PPLL programming if using ext clock */
+                               return ATOM_PPLL_INVALID;
+               }
+               pll_in_use = radeon_get_pll_use_mask(crtc);
+               if (!(pll_in_use & (1 << ATOM_PPLL1)))
+                       return ATOM_PPLL1;
+               if (!(pll_in_use & (1 << ATOM_PPLL2)))
+                       return ATOM_PPLL2;
+               DRM_ERROR("unable to allocate a PPLL\n");
+               return ATOM_PPLL_INVALID;
        } else if (ASIC_IS_DCE4(rdev)) {
                /* in DP mode, the DP ref clock can come from PPLL, DCPLL, or ext clock,
                 * depending on the asic:
@@ -1801,7 +1815,7 @@ static int radeon_atom_pick_pll(struct drm_crtc *crtc)
                                if (pll != ATOM_PPLL_INVALID)
                                        return pll;
                        }
-               } else if (!ASIC_IS_DCE41(rdev)) { /* Don't share PLLs on DCE4.1 chips */
+               } else {
                        /* use the same PPLL for all monitors with the same clock */
                        pll = radeon_get_shared_nondp_ppll(crtc);
                        if (pll != ATOM_PPLL_INVALID)