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Force text mode when GRUB reports RGB but display is text mode

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On UTM/Mac, GRUB may report a RGB framebuffer while the actual display
is in VGA text mode (0xB8000). The early VGA canary confirms text mode
works. Override fb_info to EGA_TEXT before init_drivers() so vga_init()
uses the correct text buffer instead of writing to an invisible pixel
framebuffer.

Also add EARLY_PRINT markers for SYSCALL, KBD, PROC, DRV stages.
This commit is contained in:
AI
2026-02-23 13:44:54 +00:00
parent d3ab5a5b55
commit c3c01049bf
1 changed files with 18 additions and 0 deletions
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18
src/kernel.c
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@@ -252,15 +252,33 @@ void kernel_main(uint32_t magic, uint32_t addr) {
offset_print("TSS initialized\n"); offset_print("TSS initialized\n");
init_syscalls(); init_syscalls();
EARLY_PRINT("SYSCALL ");
offset_print("Syscalls initialized\n"); offset_print("Syscalls initialized\n");
keyboard_init(); keyboard_init();
EARLY_PRINT("KBD ");
offset_print("Keyboard initialized\n"); offset_print("Keyboard initialized\n");
init_process(); init_process();
EARLY_PRINT("PROC ");
offset_print("Process subsystem initialized\n"); offset_print("Process subsystem initialized\n");
/* If the early VGA canary at 0xB8000 was visible, the display is
* definitely in text mode, regardless of what the GRUB framebuffer
* tag says. Force text mode so vga_init doesn't try to use a
* pixel framebuffer that isn't actually being displayed. */
if (fb_info.type == FB_TYPE_RGB) {
offset_print(" Overriding fb type from RGB to EGA_TEXT (early VGA visible)\n");
fb_info.type = FB_TYPE_EGA_TEXT;
fb_info.addr = 0x000B8000;
fb_info.width = 80;
fb_info.height = 25;
fb_info.bpp = 16;
fb_info.pitch = 80 * 2;
}
init_drivers(); init_drivers();
EARLY_PRINT("DRV ");
offset_print("Drivers initialized\n"); offset_print("Drivers initialized\n");
/* At this point the VGA driver has been initialized and taken over /* At this point the VGA driver has been initialized and taken over