MacSerial and Serial driver cohabitation

[Andreas Tobler]

Alain RICHARD wrote:
> There is a long waiting problem in making the two serial drivers
> (legacy serial driver named serial.o and macintosh serial driver
> named macserial.o). The problem is that the two drivers thinks there
> are the legacy one and numbers each serial port found from ttyS0 to
> ttySn. So if you try to load them simultaneously, you'll get a kernel
> fault.
>
> There are several workarounds, either :
>
> - compiles only macserial and disable legacy serial.
> - compiles the two drivers as modules and load only one (by adding
> "alias char-major-4 macserial" and "alias char-major-5 macserial" in
> your /etc/conf.modules file).

I do it this way, the macserial is built in, the serial as a module.
When you do build the serial into the kernel you get a build error:

multiple definition of `serial_console_init'


>
> This is just a hack, but the problem is worst : macserial is a serial
> driver for Z8530 chipsets and serial is a serial driver for 16x50
> UARTs. There are several cases where you may need the two drivers :
>
> a) in a powerbook when using a pcmcia modem : most, if not all, modem
> cards are based on a 16x50 UART and do need the serial.o driver.
> b) most PCI serial cards are using 16x50 UARTs
>
> Powerbooks kernels compiled by Paul Mackerras have a quick fix in the
> serial driver in order to make it skip the first 2 ttyS entries when
> compiled on PMAC architecture. This fix works but was never included
> in the main kernel because it is just a simple hack.

It's not only the skipping, there is some more needed. When you build the serial
and start the kernel then it panics since the autoconfig in serial.c is not
working on PPC.

Attached my suggestion. Here it works on a wallstreet I, which has 2 heathrow's,
that's why the offset is 4 and not 2 as mentioned above.

Andreas
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