[PATCH v6 5/9] drm/i915/cx0: Remove bus reset after every c10 transaction

[Clint Taylor]

C10 phy timeouts occur on xe3lpd if the c10 bus is reset every
transaction. Although not required by BSPEC bus resets were added for
prior platforms as a workaround. Starting with xe3_lpd this bus reset is
not necessary.

Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa at intel.com>
---
 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index 4d6e1c135bdc..c6e0cbff5201 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -224,7 +224,8 @@ static int __intel_cx0_read_once(struct intel_encoder *encoder,
 	 * down and let the message bus to end up
 	 * in a known state
 	 */
-	intel_cx0_bus_reset(encoder, lane);
+	if (DISPLAY_VER(i915) < 30)
+		intel_cx0_bus_reset(encoder, lane);
 
 	return REG_FIELD_GET(XELPDP_PORT_P2M_DATA_MASK, val);
 }
@@ -313,7 +314,8 @@ static int __intel_cx0_write_once(struct intel_encoder *encoder,
 	 * down and let the message bus to end up
 	 * in a known state
 	 */
-	intel_cx0_bus_reset(encoder, lane);
+	if (DISPLAY_VER(i915) < 30)
+		intel_cx0_bus_reset(encoder, lane);
 
 	return 0;
 }
-- 
2.25.1