drm/i915: Fix fast wake AUX sync len

Fast wake should use 8 SYNC pulses for the preamble
and 10-16 SYNC pulses for the precharge. Reduce our
fast wake SYNC count to match the maximum value.
We also use the maximum precharge length for normal
AUX transactions.

Cc: [email protected]
Cc: Jouni Högander <[email protected]>
Signed-off-by: Ville Syrjälä <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Reviewed-by: Jouni Högander <[email protected]>
(cherry picked from commit 605f7c7)
Signed-off-by: Jani Nikula <[email protected]>

Author: vsyrjala

drivers/gpu/drm/i915/display/intel_dp_aux.c

@@ -163,7 +163,7 @@ static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp,
 	      DP_AUX_CH_CTL_TIME_OUT_MAX |
 	      DP_AUX_CH_CTL_RECEIVE_ERROR |
 	      (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
-	      DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(32) |
+	      DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(24) |
 	      DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
 
 	if (intel_tc_port_in_tbt_alt_mode(dig_port))