[parisc-linux] PDC console problem.

[parisc-linux] PDC console problem.

[Naresh]

Hi,

I am trying to boot PA-Linux off a PA-RISC simulator. I am facing a
problem with the PDC console. On my first attempt, I saw the message
asking me to switch the console. So I  turned the PDC console config
option on ( the serial mux option was turned off). I added the parameter
'console=ttyB0' in 'palo.conf'. I created the device file '/dev/ttyB0'
with major/minor = 11/0 on my ramdisk. With this, the kernel boots up on
the simulator all the way upto the sash ( Stand-alone shell) prompt. I
can even see the prompt. But, the problem is that this console doesnt
seem to be accepting input from the keyboard. It is kind of like in a
locked state.

I was going through some of the FAQ and the mailing list archive and
understand that the PDC console is not a full blown console and can only
display output. Is is true that the PDC console cannot accept keyboard
input? Or am I missing something?

I also see that there are 2 versions of the PDC console driver :
'arch/parisc/kernel/pdc_cons.c' and 'drivers/char/pdc_console.c'. Both
use the device ttyB. From what I understand, the former is used before
any of the serial drivers are initialized during boot, and has only
write capability. The latter is the full-blown console driver (though I
am not sure if it has write capability). Is my understanding correct?

I am using the source tarball 'palo-latest.tar.gz' from the parisc-linux
cvs respository and cross-compiling this on an x86 box.

Regards,
Naresh.

PS: My "init" process is 'sash' and I also have a '/dev/console' device
( major=5 minor=1) on my ramdisk. The Serial driver config option is on
and I can see it being initialized in the boot path after the PDC
console.

Re: [parisc-linux] PDC console problem.

[Ryan Bradetich]

> I was going through some of the FAQ and the mailing list archive and
> understand that the PDC console is not a full blown console and can only
> display output. Is is true that the PDC console cannot accept keyboard
> input? Or am I missing something?

Hmm.. The pdc_console has both read and write capabilities.  We used the
PDC console for K/E class systems before the SerialMux driver was
written.  I am not familiar with the PDC simulator, but I would be
willing to test the pdc console again on K-Class.

Which kernel are you using?

Thanks,

- Ryan


-- 
Ryan Bradetich <rbradetich@uswest.net>

Re: [parisc-linux] PDC console problem.

[Naresh]

A small correction to the original mail: the kernel source that was compiled
was the one thats listed as latest ( cvs/linux_latest.tar.gz), which I guess
is 2.4.20-pa22. I have booted this very same kernel off an L-Class machine
with the PDC console option off.

Regards
Naresh.

Ryan Bradetich wrote:

> > I was going through some of the FAQ and the mailing list archive and
> > understand that the PDC console is not a full blown console and can only
> > display output. Is is true that the PDC console cannot accept keyboard
> > input? Or am I missing something?
>
> Hmm.. The pdc_console has both read and write capabilities.  We used the
> PDC console for K/E class systems before the SerialMux driver was
> written.  I am not familiar with the PDC simulator, but I would be
> willing to test the pdc console again on K-Class.
>
> Which kernel are you using?
>
> Thanks,
>
> - Ryan
>
> --
> Ryan Bradetich <rbradetich@uswest.net>
>
> _______________________________________________
> parisc-linux mailing list
> parisc-linux@lists.parisc-linux.org
> http://lists.parisc-linux.org/mailman/listinfo/parisc-linux

Re: [parisc-linux] PDC console problem.

[Christoph Plattner]

Hello !

The PDC driver supports both directions, IN and OUT. The PDC console 
driver was ported from the full serial driver interface, some services
not needed for poor console support are dummy routines.

So the serial console cannot be used for MODEM and other full-blown
serial devices, but is a fully functional console device including
all UNIX like features (login is working like on all other serial
devices).

He Ryan, by the way:
Why is my driver (PDC console) NOT in the mainstream kernel 2.5 ?
Even your driver covers a couple of machines, I do not see in the
MUX driver the replacement !
I agree, that the MUX driver should be used on machines with that
MUX interface. But the idea of my PDC driver was to support a fallback
driver using the ROM console usable on all machines, independent of
special setups.

I many architectures such a fallback driver is present. I remeber the
case, there was an failure in the HW-detection on my SUN Sparc-2, and
the kernel used a ROM console driver instead of the frame buffer driver
for screen/keyboard. This driver was awfully slow, and I do not
recommand it, but such a fallback driver should part of a kernel
delivery !!

So we should think about adding this driver also, independent of
al the other drivers included for console (and although the other
drivers should alwaysb be preferred).

Christoph



Ryan Bradetich wrote:
>>I was going through some of the FAQ and the mailing list archive and
>>understand that the PDC console is not a full blown console and can only
>>display output. Is is true that the PDC console cannot accept keyboard
>>input? Or am I missing something?
> 
> 
> Hmm.. The pdc_console has both read and write capabilities.  We used the
> PDC console for K/E class systems before the SerialMux driver was
> written.  I am not familiar with the PDC simulator, but I would be
> willing to test the pdc console again on K-Class.
> 
> Which kernel are you using?
> 
> Thanks,
> 
> - Ryan
> 
> 



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

Re: [parisc-linux] PDC console problem.

[Christoph Plattner]

Hello again!

There are two drivers, but they depend.

Int arch/parisc/kernel driver implements the kernel "printk()" (the
internal kernel console). This driver has NO device name, as it
cannot be access as /dev/ttyB0. BUT: This driver is register under
the name "ttyB0" to be selected as preferred device on the kernel
paramter line with "console=ttyB0".

The drivers/char driver is the full PDC serial console driver as a
TTY driver (like all the other serial drivers). This driver is
registers as MAJOR 11, MINOR 0 driver in the TTY interface and
supports fully TTY functionality (althogh some routines are dummy,
e.g. you cannot change the BAUD RATE, etc...).
The low lever routione (printing out a character, polling the keyboard)
are implemented in the first mentioned driver..

The third driver play a role is the "/dev/console" tty driver, which
assosiates the two drivers above as console driver. So the kernel
paramter line also assigns the "/dev/ttyB0" as the driver behind the
"/dev/console". And this driver is running bidirectional.

So commig to your simulator. I do not know this, but perhaps you
have simple a problem with the timing here. My PDC console drive
is in opposite to other typical TTY drivers running in POLLING
mode. The PDC interface does not support a interrupt-like handling.
So the PDC driver polls all 30ms (as far as I remember) if a key
was pressed on the PDC console. My be, the time progress has
other properties on the simulator ....

Christoph



Naresh wrote:
> Hi,
> 
> I am trying to boot PA-Linux off a PA-RISC simulator. I am facing a
> problem with the PDC console. On my first attempt, I saw the message
> asking me to switch the console. So I  turned the PDC console config
> option on ( the serial mux option was turned off). I added the parameter
> 'console=ttyB0' in 'palo.conf'. I created the device file '/dev/ttyB0'
> with major/minor = 11/0 on my ramdisk. With this, the kernel boots up on
> the simulator all the way upto the sash ( Stand-alone shell) prompt. I
> can even see the prompt. But, the problem is that this console doesnt
> seem to be accepting input from the keyboard. It is kind of like in a
> locked state.
> 
> I was going through some of the FAQ and the mailing list archive and
> understand that the PDC console is not a full blown console and can only
> display output. Is is true that the PDC console cannot accept keyboard
> input? Or am I missing something?
> 
> I also see that there are 2 versions of the PDC console driver :
> 'arch/parisc/kernel/pdc_cons.c' and 'drivers/char/pdc_console.c'. Both
> use the device ttyB. From what I understand, the former is used before
> any of the serial drivers are initialized during boot, and has only
> write capability. The latter is the full-blown console driver (though I
> am not sure if it has write capability). Is my understanding correct?
> 
> I am using the source tarball 'palo-latest.tar.gz' from the parisc-linux
> cvs respository and cross-compiling this on an x86 box.
> 
> Regards,
> Naresh.
> 
> PS: My "init" process is 'sash' and I also have a '/dev/console' device
> ( major=5 minor=1) on my ramdisk. The Serial driver config option is on
> and I can see it being initialized in the boot path after the PDC
> console.
> 
> _______________________________________________
> parisc-linux mailing list
> parisc-linux@lists.parisc-linux.org
> http://lists.parisc-linux.org/mailman/listinfo/parisc-linux
> 
> 



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