disp: msm: dsi: update the threshold time based on panel jitter

Minimum threshold time is sum of panel jitter time, prefill lines time
and buffer time of 100usec. For panels with high jitter, we can cross the
default threshold time. Update the calculation to accommodate high jitter
panels in calculating dsi clocks.

Change-Id: I93163a07c7d0b51eb3704609b4efed6c1e277761
Signed-off-by: Vara Reddy <[email protected]>

msm/dsi/dsi_panel.c

@@ -30,6 +30,7 @@
 #define DEFAULT_PANEL_JITTER_ARRAY_SIZE		2
 #define MAX_PANEL_JITTER		10
 #define DEFAULT_PANEL_PREFILL_LINES	25
+#define MIN_PREFILL_LINES      35
 
 enum dsi_dsc_ratio_type {
 	DSC_8BPC_8BPP,
@@ -3535,6 +3536,8 @@ void dsi_panel_calc_dsi_transfer_time(struct dsi_host_common_cfg *config,
 	struct msm_display_dsc_info *dsc = mode->timing.dsc;
 	struct dsi_mode_info *timing = &mode->timing;
 	struct dsi_display_mode *display_mode;
+	u32 jitter_numer, jitter_denom, prefill_lines;
+	u32 min_threshold_us, prefill_time_us;
 
 	/* Packet overlead in bits,2 bytes header + 2 bytes checksum
 	 * + 1 byte dcs data command.
@@ -3543,6 +3546,9 @@ void dsi_panel_calc_dsi_transfer_time(struct dsi_host_common_cfg *config,
 
 	display_mode = container_of(timing, struct dsi_display_mode, timing);
 
+	jitter_numer = display_mode->priv_info->panel_jitter_numer;
+	jitter_denom = display_mode->priv_info->panel_jitter_denom;
+
 	frame_time_us = mult_frac(1000, 1000, (timing->refresh_rate));
 
 	if (timing->dsc_enabled) {
@@ -3574,6 +3580,30 @@ void dsi_panel_calc_dsi_transfer_time(struct dsi_host_common_cfg *config,
 		timing->dsi_transfer_time_us =
 			mode->priv_info->mdp_transfer_time_us;
 	} else {
+
+		min_threshold_us = mult_frac(frame_time_us,
+				jitter_numer, (jitter_denom * 100));
+		/*
+		 * Increase the prefill_lines proportionately as recommended
+		 * 35lines for 60fps, 52 for 90fps, 70lines for 120fps.
+		 */
+		prefill_lines = mult_frac(MIN_PREFILL_LINES,
+				timing->refresh_rate, 60);
+
+		prefill_time_us = mult_frac(frame_time_us, prefill_lines,
+				(timing->v_active));
+
+		/*
+		 * Threshold is sum of panel jitter time, prefill line time
+		 * plus 100usec buffer time.
+		 */
+		min_threshold_us = min_threshold_us + 100 + prefill_time_us;
+
+		DSI_DEBUG("min threshold time=%d\n", min_threshold_us);
+
+		if (min_threshold_us > frame_threshold_us)
+			frame_threshold_us = min_threshold_us;
+
 		timing->dsi_transfer_time_us = frame_time_us -
 			frame_threshold_us;
 	}