[coreboot] SeaBIOS VGA failure after ctrl-alt-delete

Rudolf Marek r.marek at assembler.cz
Sat Oct 10 14:41:56 CEST 2009


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Hi Kevin

You can do good old "keyboard reset" trick.
kbd_wait();
outb(0xfe, 0x64);

This know working good.

Or throuh port 92h (less likely)

Or triple fault, which generates shutdown cycle.

load_idt(&no_idt);
_asm__ __volatile__("int3");


Or port cf9 which seems bit like chipset standard at least VIA/Intel has it.
Linux enables it if type 2 or 1 PCI config works.

u8 cf9 = inb(0xcf9) & ~6;
outb(cf9|2, 0xcf9); /* Request hard reset */
udelay(50);
outb(cf9|6, 0xcf9); /* Actually do the reset */
udelay(50);


Or we could provide a ACPI 3.0 reset register, so SeaBIOS can read this and do
reset ;)

Rudolf
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