Help debugging kernel together with X

[Fernando Herrero Carrón]

Thanks Glen,

Despite having fought many battles with the dreaded X.org update ¬¬,
this seems not to be the problem now. I tried to install a new graphics
card some time ago, before the upgrade and the result was the same.

My concern right now is the behaviour of Watchdogs, I'll start a new,
more specific thread.

Thanks,
Fernando

El mar, 26-05-2009 a las 11:39 -0400, Glen Barber escribió:
> Hi, Fernando
> 
> 2009/5/26 Fernando Herrero Carrón <fhcarron at terra.es>:
> > Hi list,
> >
> > I would like to ask for some help debugging the kernel.
> >
> > Here is the problem:
> >
> > I have a computer about five years old with an on-board graphics card
> > (SiS 661). I am trying to install an ATI Radeon 128 on the AGP port.
> > FreeBSD (FreeBSD 7.2-STABLE #10: Tue May 26 15:08:39 CEST 2009) is able
> > to start DRM and AGP without trouble. However, whenever I start X (X.Org
> > X Server 1.6.1; Release Date: 2009-4-14; Build Date: 11 May 2009
> > 12:03:27PM) the system freezes with a blank screen with some apparent
> > noisy green dots on it (reproducible, however). It does not panic, nor
> > reboot.
> >
> > Now I suspect there is some problem on the AGP bridge driver since linux
> > can run X without trouble (i.e. hardware and BIOS are ok). I have found
> > someone reporting problems with this bridge long time ago with no
> > answers (http://www.nabble.com/agp-on-sis-661-td1446998.html).
> >
> > So here I am trying to figure out where the system freezes. I have
> > recompiled my kernel adding the following options:
> >
> > options         KDB
> > options         DDB
> > options         MP_WATCHDOG
> > options         SW_WATCHDOG
> >
> > I am able to enter the debugger with ctrl+alt+esc from a console. So
> > what I am trying to do is to have watchdogd time out and the debugger
> > make a dump:
> >
> > ddb script kern.enter.watchdog=call doadump; reboot
> >
> > However, when I start X no timeout occurs, and the system stays freezed.
> > Am I missing something on the workings of watchdogd?
> >
> 
> What you're describing does not appear to be a kernel problem; it
> sounds like the typical 'Xorg update from hell' problem most
> experienced a while back.
> 
> Have a look at /usr/ports/UPDATING, and search for 'AllowEmptyInput'.
> 
> Adding the following to xorg.conf should correct the problem:
> 
> Section "ServerFlags"
>   option "AllowEmptyInput" "off"
>   option "AutoAddDevices" "off"
> EndSection
> 
> HTH
>