kernel: Optimize performance latency paths for app launch and wake-up

Improve overall responsiveness by reducing delays during
cold app start and screen wake-up. System components now
react faster to load changes, ensuring smoother and more
responsive user interactions

Signed-off-by: Mr-Morat <mtarom124@gmail.com>

Author: Mr-Morat

drivers/video/fbdev/msm/mdss_dsi.c

@@ -1916,6 +1916,68 @@ static irqreturn_t test_hw_vsync_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static int mdss_dsi_disp_wake_thread(void *data)
+{
+	static const struct sched_param max_rt_param = {
+		.sched_priority = MAX_RT_PRIO - 1
+	};
+	struct mdss_dsi_ctrl_pdata *ctrl_pdata = data;
+	struct mdss_panel_data *pdata = &ctrl_pdata->panel_data;
+
+	sched_setscheduler_nocheck(current, SCHED_FIFO, &max_rt_param);
+
+	while (1) {
+		bool should_stop;
+
+		wait_event(ctrl_pdata->wake_waitq,
+			(should_stop = kthread_should_stop()) ||
+			atomic_cmpxchg(&ctrl_pdata->disp_en,
+				       MDSS_DISPLAY_WAKING,
+				       MDSS_DISPLAY_ON) == MDSS_DISPLAY_WAKING);
+
+		if (should_stop)
+			break;
+
+		/* MDSS_EVENT_LINK_READY */
+		if (ctrl_pdata->refresh_clk_rate)
+			mdss_dsi_clk_refresh(pdata,
+					     ctrl_pdata->update_phy_timing);
+		mdss_dsi_on(pdata);
+
+		/* MDSS_EVENT_UNBLANK */
+		mdss_dsi_unblank(pdata);
+
+		/* MDSS_EVENT_PANEL_ON */
+		ctrl_pdata->ctrl_state |= CTRL_STATE_MDP_ACTIVE;
+		pdata->panel_info.esd_rdy = true;
+
+		complete_all(&ctrl_pdata->wake_comp);
+	}
+
+	return 0;
+}
+
+static void mdss_dsi_display_wake(struct mdss_dsi_ctrl_pdata *ctrl_pdata)
+{
+	if (atomic_cmpxchg(&ctrl_pdata->disp_en, MDSS_DISPLAY_OFF,
+			   MDSS_DISPLAY_WAKING) == MDSS_DISPLAY_OFF)
+		wake_up(&ctrl_pdata->wake_waitq);
+}
+
+static int mdss_dsi_fb_unblank_cb(struct notifier_block *nb,
+				  unsigned long action, void *data)
+{
+	struct mdss_dsi_ctrl_pdata *ctrl_pdata =
+		container_of(nb, typeof(*ctrl_pdata), wake_notif);
+	int *blank = ((struct fb_event *)data)->data;
+
+	/* Parse unblank events as soon as they occur */
+	if (action == FB_EARLY_EVENT_BLANK && *blank == FB_BLANK_UNBLANK)
+		mdss_dsi_display_wake(ctrl_pdata);
+
+	return NOTIFY_OK;
+}
+
 int mdss_dsi_cont_splash_on(struct mdss_panel_data *pdata)
 {
 	int ret = 0;
@@ -3029,25 +3091,12 @@ static int mdss_dsi_event_handler(struct mdss_panel_data *pdata,
 		ctrl_pdata->refresh_clk_rate = true;
 		break;
 	case MDSS_EVENT_LINK_READY:
-		if (ctrl_pdata->refresh_clk_rate)
-			rc = mdss_dsi_clk_refresh(pdata,
-				ctrl_pdata->update_phy_timing);
-
-		rc = mdss_dsi_on(pdata);
-		break;
-	case MDSS_EVENT_UNBLANK:
-		if (ctrl_pdata->on_cmds.link_state == DSI_LP_MODE)
-			rc = mdss_dsi_unblank(pdata);
+		/* The unblank notifier handles waking for unblank events */
+		mdss_dsi_display_wake(ctrl_pdata);
 		break;
 	case MDSS_EVENT_POST_PANEL_ON:
 		rc = mdss_dsi_post_panel_on(pdata);
 		break;
-	case MDSS_EVENT_PANEL_ON:
-		ctrl_pdata->ctrl_state |= CTRL_STATE_MDP_ACTIVE;
-		if (ctrl_pdata->on_cmds.link_state == DSI_HS_MODE)
-			rc = mdss_dsi_unblank(pdata);
-		pdata->panel_info.esd_rdy = true;
-		break;
 	case MDSS_EVENT_BLANK:
 		power_state = (int) (unsigned long) arg;
 		if (ctrl_pdata->off_cmds.link_state == DSI_HS_MODE)
@@ -3059,6 +3108,8 @@ static int mdss_dsi_event_handler(struct mdss_panel_data *pdata,
 		if (ctrl_pdata->off_cmds.link_state == DSI_LP_MODE)
 			rc = mdss_dsi_blank(pdata, power_state);
 		rc = mdss_dsi_off(pdata, power_state);
+		reinit_completion(&ctrl_pdata->wake_comp);
+		atomic_set(&ctrl_pdata->disp_en, MDSS_DISPLAY_OFF);
 		break;
 	case MDSS_EVENT_DISABLE_PANEL:
 		/* disable esd thread */
@@ -3807,6 +3858,23 @@ static int mdss_dsi_ctrl_probe(struct platform_device *pdev)
 #ifdef CONFIG_DEBUG_FS
 	mdss_dsi_debug_bus_init(mdss_dsi_res);
 #endif
+
+	init_completion(&ctrl_pdata->wake_comp);
+	init_waitqueue_head(&ctrl_pdata->wake_waitq);
+	ctrl_pdata->wake_thread = kthread_run(mdss_dsi_disp_wake_thread,
+					      ctrl_pdata, "mdss_display_wake");
+	if (IS_ERR(ctrl_pdata->wake_thread)) {
+		rc = PTR_ERR(ctrl_pdata->wake_thread);
+		pr_err("%s: Failed to start display wake thread, rc=%d\n",
+		       __func__, rc);
+		goto error_shadow_clk_deinit;
+	}
+
+	/* It's sad but not fatal for the fb client register to fail */
+	ctrl_pdata->wake_notif.notifier_call = mdss_dsi_fb_unblank_cb;
+	ctrl_pdata->wake_notif.priority = INT_MAX;
+	fb_register_client(&ctrl_pdata->wake_notif);
+
 	return 0;
 
 error_shadow_clk_deinit:
@@ -4276,7 +4344,8 @@ static int mdss_dsi_ctrl_remove(struct platform_device *pdev)
 	}
 
 	mdss_dsi_pm_qos_remove_request(ctrl_pdata->shared_data);
-
+	fb_unregister_client(&ctrl_pdata->wake_notif);
+	kthread_stop(ctrl_pdata->wake_thread);
 	if (msm_dss_config_vreg(&pdev->dev,
 			ctrl_pdata->panel_power_data.vreg_config,
 			ctrl_pdata->panel_power_data.num_vreg, 1) < 0)

drivers/video/fbdev/msm/mdss_dsi.h

@@ -601,6 +601,18 @@ struct mdss_dsi_ctrl_pdata {
 	bool update_phy_timing; /* flag to recalculate PHY timings */
 
 	bool phy_power_off;
+
+	struct notifier_block wake_notif;
+	struct task_struct *wake_thread;
+	struct completion wake_comp;
+	wait_queue_head_t wake_waitq;
+	atomic_t disp_en;
+};
+
+enum {
+	MDSS_DISPLAY_OFF,
+	MDSS_DISPLAY_WAKING,
+	MDSS_DISPLAY_ON
 };
 
 struct dsi_status_data {

drivers/video/fbdev/msm/mdss_mdp_ctl.c

@@ -27,6 +27,7 @@
 #include "mdss_mdp.h"
 #include "mdss_mdp_trace.h"
 #include "mdss_debug.h"
+#include "mdss_dsi.h"
 
 #define MDSS_MDP_QSEED3_VER_DOWNSCALE_LIM 2
 #define NUM_MIXERCFG_REGS 3
@@ -4269,6 +4270,14 @@ int mdss_mdp_ctl_destroy(struct mdss_mdp_ctl *ctl)
 	return 0;
 }
 
+static void mdss_mdp_wait_for_panel_on(struct mdss_panel_data *pdata)
+{
+	struct mdss_dsi_ctrl_pdata *ctrl_pdata =
+		container_of(pdata, typeof(*ctrl_pdata), panel_data);
+
+	wait_for_completion(&ctrl_pdata->wake_comp);
+}
+
 int mdss_mdp_ctl_intf_event(struct mdss_mdp_ctl *ctl, int event, void *arg,
 	u32 flags)
 {
@@ -4292,8 +4301,11 @@ int mdss_mdp_ctl_intf_event(struct mdss_mdp_ctl *ctl, int event, void *arg,
 	pr_debug("sending ctl=%d event=%d flag=0x%x\n", ctl->num, event, flags);
 
 	do {
-		if (pdata->event_handler)
+		if (pdata->event_handler) {
 			rc = pdata->event_handler(pdata, event, arg);
+			if (event == MDSS_EVENT_LINK_READY)
+				mdss_mdp_wait_for_panel_on(pdata);
+		}
 		pdata = pdata->next;
 	} while (rc == 0 && pdata && pdata->active &&
 		!(flags & CTL_INTF_EVENT_FLAG_SKIP_BROADCAST));