From cfbb0c128618554d98118ba92a48839d550053bf Mon Sep 17 00:00:00 2001
From: TermiNexus <wyt18222152539wyt@163.com>
Date: Wed, 14 Oct 2026 14:13:10 +0800
Subject: [PATCH] =?UTF-8?q?diag(vkernel):=20=5Frender()=20=E5=90=84?=
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日志证据：本轮 [dt] 心跳一行都没打印 → 桌面线程没走到“每秒”分支，即卡在第一轮循环里；
而屏幕顶部出现一小块蓝色 → 很可能执行到第一次 _render() 中途卡住（写了一半）。
宿主 QEMU 随后 abort（0x40000015 = STATUS_FATAL_APP_EXIT）。

在 _render() 埋 6 个面包屑：
  [rc] entry / bg done / taskbar done / windows done / cursor done / vblank done / flush done
最后打印的那条 = 卡住的那一步。若连 [rc] entry 都没有，则卡点在其之前
（_update_mouse / _update_keyboard / _heartbeat_check），再补那边。
定位后连同所有 [DIAG] 一并移除。
---
 VKernel/Kernel/services/desktop.vp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/VKernel/Kernel/services/desktop.vp b/VKernel/Kernel/services/desktop.vp
index 719da38..f0c0478 100644
--- a/VKernel/Kernel/services/desktop.vp
+++ b/VKernel/Kernel/services/desktop.vp
@@ -1294,6 +1294,7 @@ _perf_t_fb: uint64 = 0
 def _render():
     global _render_count, _cached_top_win
     global _perf_t_bg, _perf_t_win, _perf_t_cur, _perf_t_fb
+    serial.puts("[rc] entry\n")
     w: int = _screen_w
     h: int = _screen_h
     pitch: int = _fb_pitch
@@ -1313,8 +1314,10 @@ def _render():
             py_bg += 1
     t1: uint64 = timer.timer_get_ticks()
     _perf_t_bg += (t1 - t0)
+    serial.puts("[rc] bg done\n")
 
     _draw_taskbar(back)
+    serial.puts("[rc] taskbar done\n")
 
     t2: uint64 = timer.timer_get_ticks()
     sorted: [MAX_APP_WINDOWS]int
@@ -1335,6 +1338,7 @@ def _render():
         _draw_app_window(back, &_wins[sorted[si]])
     t3: uint64 = timer.timer_get_ticks()
     _perf_t_win += (t3 - t2)
+    serial.puts("[rc] windows done\n")
 
     # Mark cursor rows as dirty so cursor gets flushed to framebuffer
     _mark_rows_dirty(_cursor_y, CURSOR_H)
@@ -1342,8 +1346,10 @@ def _render():
     _draw_cursor(back)
     t4: uint64 = timer.timer_get_ticks()
     _perf_t_cur += (t4 - t3)
+    serial.puts("[rc] cursor done\n")
 
     _wait_vblank()
+    serial.puts("[rc] vblank done\n")
     if _dirty_count > 0:
         py_fb: int = _dirty_y_min
         while py_fb <= _dirty_y_max:
@@ -1357,6 +1363,7 @@ def _render():
                 py_fb += 1
     t5: uint64 = timer.timer_get_ticks()
     _perf_t_fb += (t5 - t4)
+    serial.puts("[rc] flush done\n")
 
     _render_count += 1