feat(gui): Enable direct boot to GUI Desktop with emergency kernel TTY fallback

- Integrate Bochs/QEMU VBE physical LFB mapping directly to hardware video memory (0xFD000000)
- Update kernel boot sequence to directly boot into GUI Desktop by default
- Fall back to Emergency Kernel TTY Mode upon GUI exit (Esc key / Exit menu item)
- Support 'nogui', 'text', 'emergency', and 'single' boot arguments to boot directly into text mode
- Remove frame limits so GUI runs persistently

drivers/video/bochs.c

@@ -1,3 +1,4 @@
+// Bochs / QEMU VBE Display Adapter Driver for SUB-OS
 #include <drivers/bochs.h>
 #include <arch/x86_64/io.h>
 #include <drivers/pci.h>
@@ -17,46 +18,6 @@ static uint16_t vbe_read(uint16_t index) {
     return inw(VBE_DISPI_IOPORT_DATA);
 }
 
-bool bochs_vbe_init(void) {
-    memset(&vbe_info, 0, sizeof(vbe_info));
-
-    // Probe VBE DISPI interface
-    uint16_t id = vbe_read(VBE_DISPI_INDEX_ID);
-    if ((id & 0xB0C0) == 0xB0C0) {
-        vbe_info.available = true;
-        vbe_info.vbe_version = id;
-        vbe_info.current_width = 1024;
-        vbe_info.current_height = 768;
-        vbe_info.current_bpp = 32;
-
-        pci_device_t* vga_pci = pci_find_class(0x03, 0x00);
-        if (vga_pci) {
-            vbe_info.lfb_phys_addr = vga_pci->bar[0] & ~0xF;
-        } else {
-            vbe_info.lfb_phys_addr = 0xFD000000;
-        }
-
-        printk(KERN_INFO "VBE: Bochs/QEMU VBE Display Adapter detected (v%04x, Linear Framebuffer: 0x%llx)\n",
-               vbe_info.vbe_version, vbe_info.lfb_phys_addr);
-        return true;
-    }
-
-    // Software emulated VBE fallback
-    vbe_info.available = true;
-    vbe_info.vbe_version = 0xB0C5;
-    vbe_info.current_width = 800;
-    vbe_info.current_height = 600;
-    vbe_info.current_bpp = 32;
-    vbe_info.lfb_phys_addr = 0xFD000000;
-
-    printk(KERN_INFO "VBE: Standard VESA/VBE Display Engine online (800x600 32bpp TrueColor)\n");
-    return true;
-}
-
-bool bochs_vbe_is_available(void) {
-    return vbe_info.available;
-}
-
 int bochs_vbe_set_mode(uint32_t width, uint32_t height, uint32_t bpp) {
     if (!vbe_info.available) return -1;
 
@@ -70,10 +31,54 @@ int bochs_vbe_set_mode(uint32_t width, uint32_t height, uint32_t bpp) {
     vbe_info.current_height = height;
     vbe_info.current_bpp = bpp;
 
-    printk(KERN_INFO "VBE: Switched resolution to %ux%u @ %u bpp\n", width, height, bpp);
+    // Connect global Framebuffer driver directly to hardware video memory
+    fb_set_hardware_lfb((uint32_t*)vbe_info.lfb_phys_addr, width, height, (uint8_t)bpp);
+
+    printk(KERN_INFO "VBE: Switched resolution to %ux%u @ %u bpp (LFB: 0x%llx)\n",
+           width, height, bpp, vbe_info.lfb_phys_addr);
     return 0;
 }
 
+bool bochs_vbe_init(void) {
+    memset(&vbe_info, 0, sizeof(vbe_info));
+
+    // Probe VBE DISPI interface
+    uint16_t id = vbe_read(VBE_DISPI_INDEX_ID);
+    if ((id & 0xB0C0) == 0xB0C0) {
+        vbe_info.available = true;
+        vbe_info.vbe_version = id;
+
+        pci_device_t* vga_pci = pci_find_class(PCI_CLASS_DISPLAY, PCI_SUBCLASS_ETHERNET); // Check Display class
+        if (!vga_pci) vga_pci = pci_find_device(0x1234, 0x1111); // QEMU Standard VGA
+        if (!vga_pci) vga_pci = pci_find_device(0x8086, 0x1237); // Intel PCI host
+
+        if (vga_pci && vga_pci->bar[0] != 0) {
+            vbe_info.lfb_phys_addr = vga_pci->bar[0] & ~0xF;
+        } else {
+            vbe_info.lfb_phys_addr = 0xFD000000;
+        }
+
+        bochs_vbe_set_mode(320, 200, 32);
+
+        printk(KERN_INFO "VBE: Bochs/QEMU VBE Display Adapter detected (v%04x, Linear Framebuffer: 0x%llx)\n",
+               vbe_info.vbe_version, vbe_info.lfb_phys_addr);
+        return true;
+    }
+
+    // Software emulated VBE fallback
+    vbe_info.available = true;
+    vbe_info.vbe_version = 0xB0C5;
+    vbe_info.lfb_phys_addr = 0xFD000000;
+    bochs_vbe_set_mode(320, 200, 32);
+
+    printk(KERN_INFO "VBE: Standard VESA/VBE Display Engine online (320x200 32bpp TrueColor)\n");
+    return true;
+}
+
+bool bochs_vbe_is_available(void) {
+    return vbe_info.available;
+}
+
 const bochs_vbe_info_t* bochs_vbe_get_info(void) {
     return &vbe_info;
 }

drivers/video/fb.c

@@ -22,13 +22,25 @@ const fb_info_t* fb_get_info(void) {
     return &fb_info;
 }
 
+void fb_set_hardware_lfb(uint32_t* lfb_addr, uint32_t width, uint32_t height, uint8_t bpp) {
+    if (lfb_addr) {
+        fb_info.address = lfb_addr;
+        fb_info.width = width;
+        fb_info.height = height;
+        fb_info.pitch = width * (bpp / 8);
+        fb_info.bpp = bpp;
+        fb_info.active = true;
+    }
+}
+
 void fb_put_pixel(uint32_t x, uint32_t y, uint32_t color) {
-    if (x < fb_info.width && y < fb_info.height) {
+    if (fb_info.address && x < fb_info.width && y < fb_info.height) {
         fb_info.address[y * fb_info.width + x] = color;
     }
 }
 
 void fb_draw_rect(uint32_t x, uint32_t y, uint32_t w, uint32_t h, uint32_t color) {
+    if (!fb_info.address) return;
     for (uint32_t j = y; j < y + h && j < fb_info.height; j++) {
         for (uint32_t i = x; i < x + w && i < fb_info.width; i++) {
             fb_info.address[j * fb_info.width + i] = color;

gui/gui_desktop.c

@@ -236,12 +236,6 @@ int gui_desktop_run(void) {
 
         // 4. Present Framebuffer to Display
         gui_gfx_present();
-
-        frame_limit++;
-        if (frame_limit > 500) {
-            // Safety break in non-interactive batch test
-            break;
-        }
     }
 
     printk(KERN_INFO "GUI: Desktop session ended, restored TTY console\n");

include/drivers/fb.h

@@ -16,6 +16,7 @@ typedef struct {
 
 void fb_init(void);
 const fb_info_t* fb_get_info(void);
+void fb_set_hardware_lfb(uint32_t* lfb_addr, uint32_t width, uint32_t height, uint8_t bpp);
 void fb_put_pixel(uint32_t x, uint32_t y, uint32_t color);
 void fb_draw_rect(uint32_t x, uint32_t y, uint32_t w, uint32_t h, uint32_t color);
 void fb_clear(uint32_t color);

kernel/main.c

@@ -66,6 +66,8 @@
 #include <drivers/virtio_gpu.h>
 #include <drivers/cpufreq.h>
 #include <drivers/virtio_input.h>
+#include <gui/gui.h>
+#include <init/init.h>
 #include <kernel/rust.h>
 #include <kernel/sub_lang.h>
 #include <kernel/cpp_kernel.h>
@@ -216,7 +218,19 @@ static void subos_modular_core_boot(void) {
     arch_enable_interrupts();
     printk(ANSI_BRIGHT_GREEN "ACTIVE\n" ANSI_RESET);
 
-    // Launch Shell
+    // Boot directly into GUI Desktop unless emergency text mode is requested
+    bool emergency_text = init_has_param("nogui") || init_has_param("text") ||
+                          init_has_param("emergency") || init_has_param("single");
+
+    if (!emergency_text) {
+        printk(KERN_INFO "INIT: Booting directly into SUB-OS Graphical Desktop Environment...\n");
+        gui_start_desktop();
+        printk(KERN_INFO "INIT: GUI session closed. Entering Emergency Kernel TTY Mode.\n");
+    } else {
+        printk(KERN_INFO "INIT: Emergency text/kernel TTY mode requested via boot parameters.\n");
+    }
+
+    // Launch Shell (Emergency TTY Mode)
     shell_run();
 
     while (1) {