[parisc-linux] [IMPORTANT] PDC & Mux console major number changed

[parisc-linux] [IMPORTANT] PDC & Mux console major number changed

[Matthew Wilcox]

Now that we've been assigned an official major number for Mux, and had
it accepted into 2.5, I've changed 2.4.20-rc1-pa2 to use that number.
So if you're using an E class, a K class or a D/R class with the funky
console thing, before you upgrade from 2.4.19, you MUST rm /dev/ttyB0
and replace it with:

mknod /dev/ttyB0 c 11 0

Yes, breakage like this sucks, but I'd rather do it now than later.

-- 
Revolutions do not require corporate support.

Re: [parisc-linux] [IMPORTANT] PDC & Mux console major number changed

[Christoph Plattner]

Hello,

I do not think it is a good idea to have the same MAJOR for PDC console
and MUX driver. Those drivers are different in concept, and the PDC
driver is valid for ALL HP machines, independent if it is a 720, 712
800er, ..... The PDC driver used the ROM support and can be used
as fall back in any case.

The MUX driver is the serial driver for those special hardware of HP.
This driver can be handled in two ways:
- Let it be an own driver with special devices, like
		/dev/ttyX0..7 or /dev/ttyM0..7 (or whatever ...)
- Let it become the "default" serial device:
		/dev/ttyS0../dev/ttyS7
   This is only possible, if there is no HP with a 16450-class UART
   and a MUX !!!

So IMO it is better to use the /dev/ttySn for MUX and 16450-like UART
instead of using MUX together with PDC !
PDC is generic and NOT for special HPs. On special HP it is the only
method to use PDC console or now MUX.


With friendly regards
Christoph P.



Matthew Wilcox wrote:
> Now that we've been assigned an official major number for Mux, and had
> it accepted into 2.5, I've changed 2.4.20-rc1-pa2 to use that number.
> So if you're using an E class, a K class or a D/R class with the funky
> console thing, before you upgrade from 2.4.19, you MUST rm /dev/ttyB0
> and replace it with:
> 
> mknod /dev/ttyB0 c 11 0
> 
> Yes, breakage like this sucks, but I'd rather do it now than later.
> 



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-------------------------------------------------------
private:	christoph.plattner@gmx.at
company:	christoph.plattner@alcatel.at

Re: [parisc-linux] [IMPORTANT] PDC & Mux console major number changed

[Matthew Wilcox]

On Thu, Nov 14, 2002 at 11:23:21PM +0100, Christoph Plattner wrote:
> I do not think it is a good idea to have the same MAJOR for PDC console
> and MUX driver. Those drivers are different in concept, and the PDC
> driver is valid for ALL HP machines, independent if it is a 720, 712
> 800er, ..... The PDC driver used the ROM support and can be used
> as fall back in any case.

I wish you'd said something before... they've been using the same major
for months now.  Anyway, there's really no point in using the PDC console
if the Mux console works, so I don't see why it's a bad thing.

> The MUX driver is the serial driver for those special hardware of HP.
> This driver can be handled in two ways:
> - Let it be an own driver with special devices, like
> 		/dev/ttyX0..7 or /dev/ttyM0..7 (or whatever ...)

Too late.  Lanana already has the registration:

11 char	Serial Mux device	(Linux/PA-RISC only)
		  0 = /dev/ttyB0	First mux port
		  1 = /dev/ttyB1	Second mux port
		    ...

(http://www.lanana.org/docs/device-list/devices.txt)

> - Let it become the "default" serial device:
> 		/dev/ttyS0../dev/ttyS7
>    This is only possible, if there is no HP with a 16450-class UART
>    and a MUX !!!

There is such a machine; D & R class can have a Mux plugin card and they
also have 16x50 UARTs provided by Lasi & Wax.  (firmware disables Lasi's
UART when this card is plugged in, but Wax's is still active).

-- 
Revolutions do not require corporate support.