Triggering kgdb on linux-2.6.37 with ttyOx

Triggering kgdb on linux-2.6.37 with ttyOx

[Tarjei Knapstad]

In recent kernels the omap serial consoles have been renamed from
ttySx to ttyOx. This seems to be an issue for kgdb. Setting kernel
boot parameters has no effect:

kgdb=ttyO2,115200n8 kgdboc=ttyO2,115200n8 kgdbwait

and attempting to trigger kgdb from the console also fails:

# echo ttyO2 > /sys/module/kgdboc/parameters/kgdboc
-bash: echo: write error: No such device

Attempting to send 'g' to sysrequest also does nothing, not sure if
there has been changes to the magic sysrq stuff as well?
# echo g > /proc/sysrq-trigger
[  120.267944] SysRq : HELP : loglevel(0-9) reBoot Crash
terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) t
haw-filesystems(J) saK show-memory-usage(M) nice-all-RT-tasks(N)
powerOff show-registers(P) show-all-timers(Q) unRaw Sync s
how-task-states(T) Unmount show-blocked-tasks(W)

I've had a look at the kgdb code, but I can't figure out what to patch
to make it understand that ttyO2 is a valid terminal. Any suggestions?

Thanks,
Tarjei

Re: Triggering kgdb on linux-2.6.37 with ttyOx

[Denys Dmytriyenko]

On Fri, Mar 18, 2011 at 09:33:13AM +0100, Tarjei Knapstad wrote:
> In recent kernels the omap serial consoles have been renamed from
> ttySx to ttyOx. This seems to be an issue for kgdb. Setting kernel
> boot parameters has no effect:
> 
> kgdb=ttyO2,115200n8 kgdboc=ttyO2,115200n8 kgdbwait
> 
> and attempting to trigger kgdb from the console also fails:
> 
> # echo ttyO2 > /sys/module/kgdboc/parameters/kgdboc
> -bash: echo: write error: No such device
> 
> Attempting to send 'g' to sysrequest also does nothing, not sure if
> there has been changes to the magic sysrq stuff as well?
> # echo g > /proc/sysrq-trigger
> [  120.267944] SysRq : HELP : loglevel(0-9) reBoot Crash
> terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) t
> haw-filesystems(J) saK show-memory-usage(M) nice-all-RT-tasks(N)
> powerOff show-registers(P) show-all-timers(Q) unRaw Sync s
> how-task-states(T) Unmount show-blocked-tasks(W)
> 
> I've had a look at the kgdb code, but I can't figure out what to patch
> to make it understand that ttyO2 is a valid terminal. Any suggestions?

Have you tried asking on the linux-omap mailing list[1]?

[1] http://vger.kernel.org/vger-lists.html#linux-omap

-- 
Denys