[Linux-ia64] lost printk's

[Linux-ia64] lost printk's

[Christian Hildner]

Hi everybody!

I want to write a low level driver for linux on ia64. During testing the
machine often crashes very heavily. After reboot most of the printk's
that have been done before the crash are lost. Maybe they are hold in
the disk cache when the crash occurs. Does anybody know how to get the
printk's written on disk?

Christian

Re: [Linux-ia64] lost printk's

[Keith Owens]

On Tue, 16 Oct 2001 08:16:05 +0200, 
Christian Hildner <christian.hildner@hob.de> wrote:
>I want to write a low level driver for linux on ia64. During testing the
>machine often crashes very heavily. After reboot most of the printk's
>that have been done before the crash are lost. Maybe they are hold in
>the disk cache when the crash occurs.

Still in memory.  printk() -> console drivers -> kernel log buffer ->
klogd (user space) -> syslogd -> kernel I/O subsystem -> disk.  Crash
too soon and the data does not get to disk.

>Does anybody know how to get the printk's written on disk?

If a crash kills the user space tasks or the disk I/O subsystem then
your printk does not get to disk.  Use a serial console and capture the
output on a second machine, that goes printk() -> console drivers ->
serial line.  Still no guarantees that you get all output, some crashes
kill the serial line driver as well.  If your problem is that bad then
use the kernel debugger, ftp://oss.sgi.com/projects/kdb/download/ia64.

Re: [Linux-ia64] lost printk's

[Nathan Straz]

On Tue, Oct 16, 2001 at 04:47:26PM +1000, Keith Owens wrote:
> If a crash kills the user space tasks or the disk I/O subsystem then
> your printk does not get to disk.  Use a serial console and capture the
> output on a second machine, that goes printk() -> console drivers ->
> serial line.  

Can anyone recommend a console server that works well with Itanium
machines?  The problem with most console servers (or inversely EFI) is
that they don't run at 115200 baud.  Is everyone just running a line to
another PC?  Is there a console server that can handle several of these
machines?
-- 
Nate Straz                                              nstraz@sgi.com
sgi, inc                                           http://www.sgi.com/
Linux Test Project                                  http://ltp.sf.net/

Re: [Linux-ia64] lost printk's

[n0ano]

Nathan-

I've used a Rocketport serial concentrator with a BigSur quite
successfully.  A single Rocketport PCI card can handle up to
32 ports.  I've never had an issue with 115200 baud, I set up
EFI to automatically boot Linux so I don't need to worry about
running EFI over the serial line and then just tell Linux to
run the serial line at 9600. 

On Tue, Oct 16, 2001 at 08:08:04AM -0500, Nathan Straz wrote:
> On Tue, Oct 16, 2001 at 04:47:26PM +1000, Keith Owens wrote:
> > If a crash kills the user space tasks or the disk I/O subsystem then
> > your printk does not get to disk.  Use a serial console and capture the
> > output on a second machine, that goes printk() -> console drivers ->
> > serial line.  
> 
> Can anyone recommend a console server that works well with Itanium
> machines?  The problem with most console servers (or inversely EFI) is
> that they don't run at 115200 baud.  Is everyone just running a line to
> another PC?  Is there a console server that can handle several of these
> machines?
> -- 
> Nate Straz                                              nstraz@sgi.com
> sgi, inc                                           http://www.sgi.com/
> Linux Test Project                                  http://ltp.sf.net/
> 
> _______________________________________________
> Linux-IA64 mailing list
> Linux-IA64@linuxia64.org
> http://lists.linuxia64.org/lists/listinfo/linux-ia64

-- 
Don Dugger
"Censeo Toto nos in Kansa esse decisse." - D. Gale
n0ano@indstorage.com
Ph: 303/652-0870x117

Re: [Linux-ia64] lost printk's

[Randolph Chung]

> Can anyone recommend a console server that works well with Itanium
> machines?  The problem with most console servers (or inversely EFI) is
> that they don't run at 115200 baud.  Is everyone just running a line to
> another PC?  Is there a console server that can handle several of these
> machines?

EFI does work at 115200 -- i use that here in my setup; but I only
have it hooked up to a PC.

randolph
-- 
   @..@                                         http://www.TauSq.org/
  (----)
 ( >__< )
 ^^ ~~ ^^

Re: [Linux-ia64] lost printk's

[Nathan Straz]

On Tue, Oct 16, 2001 at 08:37:05AM -0700, Randolph Chung wrote:
> > Can anyone recommend a console server that works well with Itanium
> > machines?  The problem with most console servers (or inversely EFI) is
> > that they don't run at 115200 baud.  Is everyone just running a line to
> > another PC?  Is there a console server that can handle several of these
> > machines?
> 
> EFI does work at 115200 -- i use that here in my setup; but I only
> have it hooked up to a PC.

Maybe I should clarify that.

Most console servers (that I've run across) don't run at 115200.
EFI _only_ runs at 115200. :(

-- 
Nate Straz                                              nstraz@sgi.com
sgi, inc                                           http://www.sgi.com/
Linux Test Project                                  http://ltp.sf.net/