VGA_SEQ_CLOCKING_MODE
reg[1] = vga_get_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE);
vga_set_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE,
vga_set_seq(VGA_REG_BASE, VGA_SEQ_CLOCKING_MODE, reg[1] & 0xdf);
REG_WRITE1(sc, VGA_SEQ_ADDRESS, VGA_SEQ_CLOCKING_MODE);