[PATCH v2 4/4] drm/i915/display: Set C10_VDR_CTRL_MSGBUS_ACCESS before phy reg read

[Jouni Högander]

According to C10 VDR Register programming sequence we need set
C10_VDR_CTRL_MSGBUS_ACCESS before accessing PHY internal registers from
MsgBus.

Fixes: 9dc619680de4 ("drm/i915/display: Add function to configure LFPS sending")
Suggested-by: Gustavo Sousa <gustavo.so...@intel.com>
Signed-off-by: Jouni Högander <jouni.hogan...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c 
b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index a203937d66db..886eff874cb7 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -3258,6 +3258,11 @@ void intel_lnl_mac_transmit_lfps(struct intel_encoder 
*encoder,
                if (!(owned_lane_mask & lane_mask))
                        continue;
 
+               if (intel_encoder_is_c10phy(encoder))
+                       intel_cx0_rmw(encoder, lane_mask, 
PHY_C10_VDR_CONTROL(1),
+                                     0, C10_VDR_CTRL_MSGBUS_ACCESS,
+                                     MB_WRITE_COMMITTED);
+
                intel_cx0_rmw(encoder, lane_mask, PHY_CMN1_CONTROL(tx, 0),
                              CONTROL0_MAC_TRANSMIT_LFPS,
                              CONTROL0_MAC_TRANSMIT_LFPS, MB_WRITE_COMMITTED);
-- 
2.43.0