driver: choose sgi_video_sync scheduler for NVIDIA

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/driver.c

@@ -19,6 +19,13 @@ void apply_driver_workarounds(struct session *ps, enum driver driver) {
 	}
 }
 
+enum vblank_scheduler_type choose_vblank_scheduler(enum driver driver) {
+	if (driver & DRIVER_NVIDIA) {
+		return VBLANK_SCHEDULER_SGI_VIDEO_SYNC;
+	}
+	return VBLANK_SCHEDULER_PRESENT;
+}
+
 enum driver detect_driver(xcb_connection_t *c, backend_t *backend_data, xcb_window_t window) {
 	enum driver ret = 0;
 	// First we try doing backend agnostic detection using RANDR

src/backend/driver.h

@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <xcb/xcb.h>
 
+#include "config.h"
 #include "utils.h"
 
 struct session;
@@ -41,6 +42,8 @@ enum driver detect_driver(xcb_connection_t *, struct backend_base *, xcb_window_
 
 /// Apply driver specified global workarounds. It's safe to call this multiple times.
 void apply_driver_workarounds(struct session *ps, enum driver);
+/// Choose a vblank scheduler based on the driver.
+enum vblank_scheduler_type choose_vblank_scheduler(enum driver driver);
 
 // Print driver names to stdout, for diagnostics
 static inline void print_drivers(enum driver drivers) {

src/picom.c

@@ -1493,18 +1493,24 @@ static bool redirect_start(session_t *ps) {
 		ps->frame_pacing = false;
 	}
 
+	// Re-detect driver since we now have a backend
+	ps->drivers = detect_driver(ps->c.c, ps->backend_data, ps->c.screen_info->root);
+	apply_driver_workarounds(ps, ps->drivers);
+
 	if (ps->present_exists && ps->frame_pacing) {
 		// Initialize rendering and frame timing statistics, and frame pacing
 		// states.
 		ps->last_msc_instant = 0;
 		ps->last_msc = 0;
 		ps->last_schedule_delay = 0;
 		render_statistics_reset(&ps->render_stats);
-		enum vblank_scheduler_type scheduler_type = VBLANK_SCHEDULER_PRESENT;
+		enum vblank_scheduler_type scheduler_type =
+		    choose_vblank_scheduler(ps->drivers);
 		if (ps->o.debug_options.force_vblank_scheduler != LAST_VBLANK_SCHEDULER) {
 			scheduler_type =
 			    (enum vblank_scheduler_type)ps->o.debug_options.force_vblank_scheduler;
 		}
+		log_info("Using vblank scheduler: %s.", vblank_scheduler_str[scheduler_type]);
 		ps->vblank_scheduler = vblank_scheduler_new(
 		    ps->loop, &ps->c, session_get_target_window(ps), scheduler_type);
 		if (!ps->vblank_scheduler) {
@@ -1523,10 +1529,6 @@ static bool redirect_start(session_t *ps) {
 	ps->redirected = true;
 	ps->first_frame = true;
 
-	// Re-detect driver since we now have a backend
-	ps->drivers = detect_driver(ps->c.c, ps->backend_data, ps->c.screen_info->root);
-	apply_driver_workarounds(ps, ps->drivers);
-
 	root_damaged(ps);
 
 	// Repaint the whole screen