xserver on OpenGL

[Jon Smirl]

A while ago (last Feb) I built a special version of UML (user mode linux) that
would run any Linux 2.6 device driver unchanged. It works because you install
the hardware in the host system and then don't load any host device drivers for
it. Instead you load a special one that turns interrupts into signals. Inside of
UML I repimplemented all of the needed system calls such as ioremap(). This
really works, you can take an unchanged 2.6 device driver and run it in user
mode.

With this special UML I was able to use the debugger on fbdev and DRM drivers in
my single machine. You just bring the UML kernel up in gdb and set breakpoints
in the driver. You can even use modules but it is more complicated, much simpler
just to build the driver in. I got this working with network drivers too. If you
crash the 'kernel' just kill it and run it again.

The downside is that I contributed the code to UML in Feb but the maintainer
still hasn't merged it. So it has suffered bit rot since the kernel has been
changing. Needless to say I am a little annoyed at the maintainer.

--- Kendall Bennett <KendallB@scitechsoft.com> wrote:
> We generally do all debugging on a separate machine and use TCP/IP or 
> parallel port for the connection. For drivers we develop from Windows 
> 2000/XP and run the debug code under 32-bit DOS or OS/2 console mode 
> using Open Watcom (and with Open Watcom 1.2 we can debug our driver 
> modules with full source code debugging ;-). For XFree86 debugging I ssh 
> into a Red Hat 7.3 box to build and debug the modules (my main box is Red 
> Hat 8.0). Unfortunately the hacked up GDB does not work very well with 
> anything by XFree86 7.3, so if we debug on 8.0 we cannot debug the 
> XFree86 driver modules with source code.
> 
> Also the Linux port of Open Watcom is coming along nicely, and I am 
> hoping eventually I can ditch Windows XP and instead build on Linux. I 
> doubt I will debug on Linux except for Linux specific stuff though, as we 
> have a pretty solid DOS or OS/2 console boot that can both handle hard 
> crashes and re-boot quickly in case of failure. When Open Watcom is done 
> for Linux, I can build on Linux and remote debug via TCP/IP or parallel 
> port to OS/2 or DOS (actually you can do that today if you build from the 
> latest source code). Even with ext-3 I have had hard crashes during 
> debugging that have taken out my entire Linux distro requiring me to 
> restore it from a Drive Image image.
> 
> Regards,
> 
> ---
> Kendall Bennett
> Chief Executive Officer
> SciTech Software, Inc.
> Phone: (530) 894 8400
> http://www.scitechsoft.com
> 
> ~ SciTech SNAP - The future of device driver technology! ~
> 
> 
> _______________________________________________
> Xserver mailing list
> Xserver@pdx.freedesktop.org
> http://pdx.freedesktop.org/cgi-bin/mailman/listinfo/xserver


=====
Jon Smirl
jonsmirl@yahoo.com

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