[Intel-gfx] [PATCH] drm/i915/mtl: Fix SSC selection for MPLLA

[Radhakrishna Sripada]

Driver does not clear the default SSC for MPLLA. This causes link training
failure when trying to use 10G and 20G rates. Fix the behaviour and enable ssc
only when we really want.

Fixes: 237e7be0bf57 ("drm/i915/mtl: For DP2.0 10G and 20G rates use MPLLA")
Cc: Mika Kahola <mika.kahola at intel.com>
Cc: Clint Taylor <Clinton.A.Taylor at intel.com>
Cc: Khaled Almahallawy <khaled.almahallawy at intel.com>
Cc: Arun R Murthy <arun.r.murthy at intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
---
 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index f235df5646ed..1b00ef2c6185 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -2434,7 +2434,8 @@ static void intel_program_port_clock_ctl(struct intel_encoder *encoder,
 
 	intel_de_rmw(i915, XELPDP_PORT_CLOCK_CTL(encoder->port),
 		     XELPDP_LANE1_PHY_CLOCK_SELECT | XELPDP_FORWARD_CLOCK_UNGATE |
-		     XELPDP_DDI_CLOCK_SELECT_MASK | XELPDP_SSC_ENABLE_PLLB, val);
+		     XELPDP_DDI_CLOCK_SELECT_MASK | XELPDP_SSC_ENABLE_PLLA |
+		     XELPDP_SSC_ENABLE_PLLB, val);
 }
 
 static u32 intel_cx0_get_powerdown_update(u8 lane_mask)
-- 
2.34.1