static const struct dio200_board dio200_isa_boards[] = {
        {
                .name = "pc212e",
-               .mainsize = DIO200_IO_SIZE,
                .layout = {
                        .n_subdevs = 6,
                        .sdtype = {sd_8255, sd_8254, sd_8254, sd_8254, sd_8254,
        },
        {
                .name = "pc214e",
-               .mainsize = DIO200_IO_SIZE,
                .layout = {
                        .n_subdevs = 4,
                        .sdtype = {sd_8255, sd_8255, sd_8254, sd_intr},
        },
        {
                .name = "pc215e",
-               .mainsize = DIO200_IO_SIZE,
                .layout = {
                        .n_subdevs = 5,
                        .sdtype = {sd_8255, sd_8255, sd_8254, sd_8254, sd_intr},
        },
        {
                .name = "pc218e",
-               .mainsize = DIO200_IO_SIZE,
                .layout = {
                        .n_subdevs = 7,
                        .sdtype = {sd_8254, sd_8254, sd_8255, sd_8254, sd_8254,
        },
        {
                .name = "pc272e",
-               .mainsize = DIO200_IO_SIZE,
                .layout = {
                        .n_subdevs = 4,
                        .sdtype = {sd_8255, sd_8255, sd_8255, sd_intr},
 
 static int dio200_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
-       const struct dio200_board *thisboard = comedi_board(dev);
        unsigned int irq;
        int ret;
 
        irq = it->options[1];
 
-       ret = comedi_request_region(dev, it->options[0], thisboard->mainsize);
+       ret = comedi_request_region(dev, it->options[0], 0x20);
        if (ret)
                return ret;