Fix PS/2 mouse ISR blocking; convert USB polling & GFX refresh to processes; remove dead scheduler

PS/2 Mouse:
- Fix ISR spin-blocking by reading port $60 directly with inb() instead
  of calling mouse_read(), which uses mouse_wait_long (100k iterations)
  and would stall the interrupt handler waiting for the next packet byte.

Timer (PIT):
- Increase PIT frequency from ~1024 Hz to ~8 kHz (divisor 1193 -> 149)
  for more granular timer ticks.

Graphics Refresh:
- Replace timer-hook-driven rendering (driver/timers/graphicsrefresh)
  with a dedicated 'gfxd' process that runs a continuous render loop,
  keeping the vCPU active to avoid NEM/Hyper-V pause-loop descheduling.
- Move uidebug from driver/video/ to prog/.
- Update FPS calculation to account for 8 kHz tick rate.

USB Hotplug:
- Replace timer-hook-driven polling (driver/timers/usbhotplug) with a
  dedicated 'usbd' daemon process that sleeps 1s between poll cycles.
- Add bounds check in usbcore.usb_check_hotplug for empty HC list.

Cleanup:
- Remove old scheduler unit (superseded by processmanager/contextswitcher).
- Remove tss unit and tss.init() call from kernel.
- Remove unused syslog import from contextswitcher.
- Reduce BASE_QUANTUM from 8 to 5.

src/contextswitcher.pas

@@ -29,14 +29,11 @@ unit contextswitcher;
 interface
 
 uses
-    idt, isrmanager, processmanager, proctypes, util, syslog, tracer;
+    idt, isrmanager, processmanager, proctypes, util, tracer;
 
 { Initialise: overwrite IDT gate 32 with our custom ISR. }
 procedure init;
 
-{ No idle ESP variable needed — idle is now a formal process (PID 0)
-  with its SavedESP managed like any other process. }
-
 implementation
 
 { -----------------------------------------------------------------------

src/driver/bus/usb/usbcore.pas

@@ -957,11 +957,14 @@ end;
 procedure usb_check_hotplug;
 var
     i    : uint32;
+    count: uint32;
     hc   : PUSBHCDriver;
     port : uint8;
 begin
     if HCList = nil then exit;
-    for i := 0 to LL_Size(HCList) - 1 do begin
+    count := LL_Size(HCList);
+    if count = 0 then exit;
+    for i := 0 to count - 1 do begin
         hc := PUSBHCDriver(LL_Get(HCList, i));
         if (hc <> nil) and hc^.PortChangePending then begin
             hc^.PortChangePending := false;

src/driver/hid/ps2/ps2_mouse.pas

@@ -119,8 +119,12 @@ var
     x32, y32 : sint32;
     r : pchar;
 begin
+    { mouse_wait(0) checks OBF with a short timeout (100 iterations).
+      When it returns true, data is ready — read it directly with inb($60).
+      Do NOT call mouse_read here: it uses mouse_wait_long (100k iterations)
+      and would spin-block the ISR if the next packet byte hasn't arrived yet. }
     while mouse_wait(0) do begin
-        b := mouse_read;
+        b := inb($60);
         if Cycle = 0 then begin
             if (b AND $08) = $08 then begin
                 Mouse_Byte[Cycle] := b;

src/driver/timers/TMR_0_ISR.pas

@@ -13,7 +13,7 @@
 //  limitations under the License.
 
 { 
-	Driver->Timer->TMR_0_ISR - 1024hz Timer Driver.
+	Driver->Timer->TMR_0_ISR - 8khz Timer Driver.
 	
 	@author(Kieron Morris <[email protected]>)
 }
@@ -37,7 +37,7 @@ var
     Hooks : Array[1..MAX_HOOKS] of pp_hook_method;
     Registered : boolean = false;
 
-procedure Main; //IRQ0, 1024.19hz aprox
+procedure Main; //IRQ0, ~8001hz
 var
     i : integer;
 
@@ -54,7 +54,7 @@ procedure register();
 begin
     if not registered then begin
         asm
-            mov ax, 1193
+            mov ax, 149
             out $40, al
             mov al, ah
             out $40, al

src/driver/timers/graphicsrefresh.pas

@@ -1,54 +0,0 @@
-{
-    Driver->Timer->GraphicsRefresh - Timer-driven graphics refresh at ~120FPS.
-
-    Hooks into the 1024Hz timer (TMR_0_ISR) and calls the desktop, uidebug,
-    LVGL and video flush routines every ~9 ticks (1024/9 ≈ 113.8 FPS).
-
-    @author(Kieron Morris <[email protected]>)
-}
-unit graphicsrefresh;
-
-interface
-
-procedure init;
-
-implementation
-
-uses
-    util,
-    TMR_0_ISR,
-    desktop,
-    uidebug,
-    lvgl,
-    video,
-    windows,
-    syslog;
-
-const
-    { 1024 / 4 ≈ 256 FPS }
-    TICKS_PER_FRAME = 4;
-
-var
-    TickCounter : uint32;
-
-procedure on_tick(data : void);
-begin
-    TickCounter := TickCounter + 1;
-    if TickCounter >= TICKS_PER_FRAME then begin
-        TickCounter := 0;
-        windows.reapOrphanedWindows;
-        desktop.update;
-        uidebug.update;
-        lvgl_handler;
-        video.Flush;
-    end;
-end;
-
-procedure init;
-begin
-    TickCounter := 0;
-    TMR_0_ISR.hook(uint32(@on_tick));
-    syslog.logln('GFXREFRESH', 'Hooked into 1024Hz timer (~120 FPS).');
-end;
-
-end.

src/driver/timers/usbhotplug.pas

@@ -1,46 +0,0 @@
-{
-    Driver->Timer->USBHotplug - Timer-driven USB hotplug polling at ~1Hz.
-
-    Hooks into the 1024Hz timer (TMR_0_ISR) and calls
-    usbcore.usb_check_hotplug every 1024 ticks (approximately once per second).
-
-    @author(Kieron Morris <[email protected]>)
-}
-unit usbhotplug;
-
-interface
-
-procedure init;
-
-implementation
-
-uses
-    util,
-    TMR_0_ISR,
-    usbcore,
-    syslog;
-
-const
-    { 1024 ticks at 1024Hz ≈ 1 second }
-    TICKS_PER_POLL = 1024;
-
-var
-    TickCounter : uint32;
-
-procedure on_tick(data : void);
-begin
-    TickCounter := TickCounter + 1;
-    if TickCounter >= TICKS_PER_POLL then begin
-        TickCounter := 0;
-        usbcore.usb_check_hotplug;
-    end;
-end;
-
-procedure init;
-begin
-    TickCounter := 0;
-    TMR_0_ISR.hook(uint32(@on_tick));
-    syslog.logln('USBHOTPLUG', 'Hooked into 1024Hz timer (~1Hz polling).');
-end;
-
-end.

src/include/proctypes.pas

@@ -18,7 +18,7 @@ const
     PROCESS_STACK_SIZE = 8192;
 
     { Base quantum multiplier: quantum = Priority * BASE_QUANTUM ticks }
-    BASE_QUANTUM = 8;
+    BASE_QUANTUM = 5;
 
 type
     { Forward declaration }

src/kernel.pas

@@ -25,7 +25,7 @@ interface
 uses
      multiboot, bios_data_area,
      util,
-     gdt, idt, isr, irq, tss,
+     gdt, idt, isr, irq,
      TMR_0_ISR,
      syslog, stdio,
      keyboard, mouse,
@@ -33,7 +33,6 @@ uses
      vmemorymanager, pmemorymanager, lmemorymanager,
      tracer,
      drivermanagement,
-     scheduler,
      progmanager,
      processmanager, contextswitcher,
      testprocs,
@@ -67,7 +66,7 @@ uses
      base64,
      rand,
      hashmap, vfs,
-     video, vesa, doublebuffer, color, lvgl, desktop, uidebug,
+     video, vesa, doublebuffer, color, lvgl, desktop, uidebug, windows,
      vterminal,
      graphicsrefresh, usbhotplug,
      fifo, cfifo, cfifols, lifo, circ, minh, maxh, prio;
@@ -170,9 +169,6 @@ begin
      stdio.init();
      stdio.registerCommand('BSOD', @terminal_command_bsod, 'Force a Panic Screen.');
 
-     tss.init();
-     scheduler.init();
-
      { CPUID }
      syslog.logln('CPU', 'Init begin');
      cpu.init();

src/prog/graphicsrefresh.pas

@@ -0,0 +1,76 @@
+{
+    prog->GraphicsRefresh - Continuous graphics rendering process.
+
+    Spawns a dedicated render process that loops indefinitely, driving the
+    desktop, LVGL and video-flush pipeline.  The loop does real work every
+    iteration (especially the 7.3 MB SSE framebuffer copy in video.Flush),
+    which keeps the vCPU active so the NEM/Hyper-V back-end never
+    deschedules it and starves the PIT of interrupts.
+
+    @author(Kieron Morris <[email protected]>)
+}
+unit graphicsrefresh;
+
+interface
+
+procedure init;
+
+implementation
+
+uses
+    desktop,
+    uidebug,
+    lvgl,
+    video,
+    windows,
+    processmanager,
+    proctypes,
+    syslog,
+    TMR_0_ISR;
+
+{ Render process entry point — runs as a normal scheduled process with
+  interrupts enabled.  Continuously drives the full render pipeline so
+  the vCPU is always executing real work (no HLT / PAUSE spin-waits
+  that would trigger pause-loop exits under NEM/Hyper-V). }
+
+const
+    TICKS_PER_FRAME = 32;  { target ticks per frame; adjust as needed to balance refresh rate and CPU usage }
+
+var
+    LAST_UPDATE : uint32 = 0;
+    CURRENT_TICK : uint32 = 0;
+
+procedure render_loop(ctx : PProcessContext);
+var
+    should_update : boolean;
+
+begin
+    while true do begin
+        should_update := (CURRENT_TICK - LAST_UPDATE) >= TICKS_PER_FRAME;
+        should_update := should_update or (CURRENT_TICK < LAST_UPDATE);  { handle tick counter wraparound }
+        if (should_update) then begin
+            LAST_UPDATE := CURRENT_TICK;
+            windows.reapOrphanedWindows;
+            desktop.update;
+            uidebug.update;
+            lvgl_handler;
+            video.Flush;
+        end;
+    end;
+end;
+
+procedure tick;
+begin
+    { This function is called on every timer tick (interrupt 32) via the ISR hooks.
+      It can be used to trigger periodic tasks without needing a dedicated process. }
+    CURRENT_TICK := CURRENT_TICK + 1;
+end;
+
+procedure init;
+begin
+    TMR_0_ISR.hook(uint32(@tick));  { Register the tick handler to run on every timer interrupt }
+    processmanager.create('gfxd', @render_loop, nil, 5);
+    syslog.logln('gfxd', 'Render process spawned.');
+end;
+
+end.

src/prog/uidebug.pas

@@ -365,7 +365,7 @@ begin
     now_tick := lvgl_get_ticks;
 
     if (now_tick - last_tick) >= FPS_INTERVAL then begin
-        current_fps := safeDiv32(frame_count * 1000, now_tick - last_tick);
+        current_fps := safeDiv32(frame_count * 8000, now_tick - last_tick);
         frame_count := 0;
         last_tick := now_tick;
 

src/prog/usbhotplug.pas

@@ -0,0 +1,38 @@
+{
+    Prog->USBHotplug - USB hotplug daemon process.
+
+    Spawns a dedicated 'usbd' process that polls for USB port changes
+    approximately once per second using processmanager.proc_sleep_ms.
+
+    @author(Kieron Morris <[email protected]>)
+}
+unit usbhotplug;
+
+interface
+
+procedure init;
+
+implementation
+
+uses
+    usbcore,
+    processmanager,
+    proctypes,
+    syslog;
+
+{ USB daemon process entry point — polls for hotplug events once per second. }
+procedure usbd_loop(ctx : PProcessContext);
+begin
+    while true do begin
+        usbcore.usb_check_hotplug;
+        processmanager.proc_sleep_ms(1000);
+    end;
+end;
+
+procedure init;
+begin
+    processmanager.create('usbd', @usbd_loop, nil, 2);
+    syslog.logln('usbd', 'USB hotplug daemon spawned.');
+end;
+
+end.

src/scheduler.pas

@@ -1,132 +0,0 @@
-//  Copyright 2021 Kieron Morris
-//
-//  Licensed under the Apache License, Version 2.0 (the "License");
-//  you may not use this file except in compliance with the License.
-//  You may obtain a copy of the License at
-//
-//  http://www.apache.org/licenses/LICENSE-2.0
-//
-//  Unless required by applicable law or agreed to in writing, software
-//  distributed under the License is distributed on an "AS IS" BASIS,
-//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//  See the License for the specific language governing permissions and
-//  limitations under the License.
-
-{ 
-	Scheduler - Schedules Context Switches.
-	
-	@author(Kieron Morris <[email protected]>)
-}
-
-unit scheduler;
-
-interface
-
-uses
-    syslog, stdio,
-    TMR_0_ISR,
-    lmemorymanager;
-
-const
-    Quantum = 64;
-
-type
-    TTaskState = packed record
-        //EAX, EDX, 
-    end;
-    TScheduler_Entry = packed record
-        ThreadID : uint32;
-        Priority : uint8;
-        Delta    : uint32;
-        Next     : void;
-    end;
-    PScheduler_Entry = ^TScheduler_Entry;
-
-var
-    Active : Boolean;
-
-procedure init;
-procedure add_task(priority : uint8);
-
-implementation
-
-var
-   Tick         : uint32;
-   Root_Task    : PScheduler_Entry = nil;
-   Current_Task : PScheduler_Entry = nil;
-
-procedure context_switch();
-begin
-    Current_Task:= PScheduler_Entry(Current_Task^.Next);
-end;
-
-procedure add_task(priority : uint8);
-var
-    new_task : PScheduler_Entry;
-    task     : PScheduler_Entry;
-    i        : uint32;
-
-begin
-    new_task:= PScheduler_Entry(kalloc(sizeof(TScheduler_Entry)));
-    new_task^.Priority:= priority;
-    new_task^.Delta:= Tick;
-    new_task^.Next:= void(Root_Task);
-    task:= Root_Task;
-    i:= 1;
-    while PScheduler_Entry(task^.next) <> Root_Task do begin
-        i:= i+1;
-        task:= PScheduler_Entry(task^.next);
-    end;
-    task^.next:= void(new_task);
-    new_task^.ThreadID:= i;
-end;
-
-procedure delta(data : void);
-begin
-    If Active then begin
-        Tick:= Tick + 1;
-        If Tick = 0 then context_switch();
-        If (Current_Task^.Delta + (Current_Task^.Priority * Quantum)) <= Tick then context_switch();
-    end;
-end;
-
-procedure terminal_command_tasks(params : PParamList; stdin_buf, stdout_buf, stderr_buf : POutBuf);
-var
-    list : PScheduler_Entry;
-
-begin
-    stdio.bufWriteStrLn(stdout_buf, 'ThreadID - Priority - Delta');
-    list:= Root_Task;
-    stdio.bufWriteInt(stdout_buf, list^.ThreadID);
-    stdio.bufWriteStr(stdout_buf, '        - ');
-    stdio.bufWriteInt(stdout_buf, list^.Priority);
-    stdio.bufWriteStr(stdout_buf, '        - ');
-    stdio.bufWriteIntLn(stdout_buf, list^.Delta);
-    list:= PScheduler_Entry(list^.Next);
-    while list <> Root_Task do begin
-        stdio.bufWriteInt(stdout_buf, list^.ThreadID);
-        stdio.bufWriteStr(stdout_buf, '        - ');
-        stdio.bufWriteInt(stdout_buf, list^.Priority);
-        stdio.bufWriteStr(stdout_buf, '        - ');
-        stdio.bufWriteIntLn(stdout_buf, list^.Delta);
-        list:= PScheduler_Entry(list^.Next);
-    end;
-end;
-
-procedure init;
-begin
-    syslog.logln('SCHEDULER','INIT BEGIN.');
-    Root_Task:= PScheduler_Entry(kalloc(sizeof(TScheduler_Entry)));
-    Root_Task^.ThreadID:= 0;
-    Root_Task^.Priority:= 1;
-    Root_Task^.Delta:= 0;
-    Root_Task^.Next:= void(Root_Task);
-    Current_Task:= Root_Task;
-    Tick:= 0;
-    Active:= False;
-    TMR_0_ISR.hook(uint32(@delta));
-    //stdio.registerCommand('TASKS', @terminal_command_tasks, 'List Active Processes.');
-    syslog.logln('SCHEDULER','INIT END.');
-end;
-
-end.

src/tss.pas

@@ -1,111 +0,0 @@
-//  Copyright 2021 Kieron Morris
-//
-//  Licensed under the Apache License, Version 2.0 (the "License");
-//  you may not use this file except in compliance with the License.
-//  You may obtain a copy of the License at
-//
-//  http://www.apache.org/licenses/LICENSE-2.0
-//
-//  Unless required by applicable law or agreed to in writing, software
-//  distributed under the License is distributed on an "AS IS" BASIS,
-//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//  See the License for the specific language governing permissions and
-//  limitations under the License.
-
-{ 
-	TSS - Task State Segment (stub).
-	
-	@author(Kieron Morris <[email protected]>)
-}
-unit tss;
-
-interface
-
-uses
-    gdt,
-    vmemorymanager,
-    syslog;
-
-type
-    TTaskStateSegment = packed record
-        link : uint16;
-        link_h : uint16;
-
-        esp0 : uint32;
-        ss0 : uint16;
-        ss0_h : uint16;
-
-        esp1 : uint32;
-        ss1 : uint16;
-        ss1_h : uint16;
-
-        esp2 : uint32;
-        ss2 : uint16;
-        ss2_h : uint16;
-
-        cr3 : uint32;
-        eip : uint32;
-        eflags : uint32;
-
-        eax : uint32;
-        ecx : uint32;
-        edx : uint32;
-        ebx : uint32;
-
-        esp : uint32;
-        ebp : uint32;
-        esi : uint32;
-        edi : uint32;
-        es : uint16;
-        es_h : uint16;
-        cs : uint16;
-        cs_h : uint16;
-        ss : uint16;
-        ss_h : uint16;
-        ds : uint16;
-        ds_h : uint16;
-        fs : uint16;
-        fs_h : uint16;
-        gs : uint16;
-        gs_h : uint16;
-        ldt : uint16;
-        ldt_h : uint16;
-        trap : uint16;
-        iomap : uint16;
-    end;
-    PTaskStateSegment = ^TTaskStateSegment;
-
-var
-    TaskStateSegment : TTaskStateSegment;
-    ptrTaskStateSegment : PTaskStateSegment = @TaskStateSegment;
-
-procedure init;
-
-implementation
-
-procedure init;
-var
-    cESP : uint32;
-    cCR3 : uint32;
-
-begin
-    syslog.logln('TSS','INIT BEGIN.');
-    ptrTaskStateSegment^.ss0:= $08;
-    ptrTaskStateSegment^.iomap:= sizeof(TTaskStateSegment)-1;
-    asm
-        MOV cESP, ESP 
-        MOV EAX, CR3
-        MOV cCR3, EAX
-    end;
-    ptrTaskStateSegment^.esp0:= cESP;
-    ptrTaskStateSegment^.CR3:= cCR3;
-    gdt.set_gate($05, uint32(ptrTaskStateSegment) - KERNEL_VIRTUAL_BASE, sizeof(TTaskStateSegment) - 1, $89, $40); //OFFSET: 40
-    gdt.reload;
-    asm
-        mov AX, 40
-        ltr AX
-    end;
-    syslog.logln('TSS','INIT END.');
-end;
-
-end.