disp: msm: sde: consider max of actual and default prefill lines

In transfer-time calculation remove fixed prefill lines assumption
and consider max of default prefill lines and prefill lines specified
from the panel timing info.

For panels with higher porches exceeding default prefill lines
alternate framedrops can occur if transfer-time exceeds RSC static
waketup time as actual prefill lines are considered in RSC static
wakeup timer calculation. This change ensures transfer-time is with
in RSC static wakeup time.

Change-Id: I3663f9c9179efb7225a748f456f2a2cf167d241e
Signed-off-by: Prabhanjan Kandula <[email protected]>

msm/dsi/dsi_panel.c

@@ -3946,6 +3946,7 @@ void dsi_panel_calc_dsi_transfer_time(struct dsi_host_common_cfg *config,
 	struct dsi_mode_info *timing = &mode->timing;
 	struct dsi_display_mode *display_mode;
 	u32 jitter_numer, jitter_denom, prefill_lines;
+	u32 default_prefill_lines, actual_prefill_lines;
 	u32 min_threshold_us, prefill_time_us, max_transfer_us, packet_overhead;
 	u16 bpp;
 
@@ -4009,8 +4010,12 @@ void dsi_panel_calc_dsi_transfer_time(struct dsi_host_common_cfg *config,
 	 * Increase the prefill_lines proportionately as recommended
 	 * 40lines for 60fps, 60 for 90fps, 120lines for 120fps, and so on.
 	 */
-	prefill_lines = mult_frac(MIN_PREFILL_LINES,
-			timing->refresh_rate, 60);
+	default_prefill_lines = mult_frac(MIN_PREFILL_LINES, timing->refresh_rate, 60);
+
+	actual_prefill_lines = timing->v_back_porch + timing->v_front_porch + timing->v_sync_width;
+
+	/* consider the max of default prefill lines and actual prefill lines */
+	prefill_lines = max(actual_prefill_lines, default_prefill_lines);
 
 	prefill_time_us = mult_frac(frame_time_us, prefill_lines,
 			(timing->v_active));