Xbox Linux kernel patches

Hi!

I am Michael Steil from the Xbox Linux Project. As you might already know,
we successfully run standard distributions on ("modded") Microsoft Xbox
gaming consoles with only minimal kernel changes.

Our question is now what way our patches will have to be in order to have a
chance for them to be accepted into the main kernel tree. I'll tell you a
bit about our kernel changes first:

1) PCI chipset bugfix
The Xbox chipset has a PCI bug that makes the system hang when reading from
00:00.2 or 00:00.3 in the PCI configuration space. We have added a check
that ignores these devices, embraced by #ifdef CONFIG_XBOX in
drivers/pci/pci.c

2) System timer fix
The system timer runs about 6% faster than on a PC. We have added a #ifdef
CONFIG_XBOX section to include/asm-i386/timex.h

3) Shutdown/Reboot
The Xbox doesn't support standardized APM to shut down and doesn't have a
keyboard controller to reset the system. We have added code to shut down
and reboot the Xbox in arch/i386/kernel/process.c.

4) No keyboard controller
There already seems to be a patch available that doesn't print 100 warnings
and allocate IRQ1 for the keyboard if there is no keyboard controller
present and we add the command line parameter "kbd-reset". This patch is in
2.4.19-16mdk, but not in plain vanilla 2.4.19. Without this patch, we have
an interrupt conflict on IRQ1.

There are some more drivers we're working on at the moment:

1) FATX driver
The Xbox uses a derivative of the MS-DOS FAT filesystem, but it's a lot
simplified and completely legacy-free. Though, the file allocation table
structure and the basic ideas of directory entries remain the same. We have
done small changes to fs/fat/* and added a directory fs/fatx.

2) Xpad & remote control drivers
The Xpad (Xbox gamepad) driver module is already available in your latest
development kernel, we can soon add additional or updated drivers for
Xbox-specific (USB) hardware.

So these are our questions now:

Do we have a chance for our kernel fixes for the Xbox to be included into
the standard kernel? All our changes are tiny and #ifdef CONFIG_XBOX and
change nothing on a i386 PC or on any other architecture.

Would it be better to have a runtime check at kernel initialization to
detect the Xbox and put all Xbox specific code between if (xbox) {}?

Can our FATX driver be accepted into the main kernel? It has been
impossible to implement FATX on top of FAT without making the FATX code a
bit more general. We hope that it wasn't too many changes there. By the
way, FATX doesn't only make sense on the Xbox, it's a multi-purpose
filesystem that might also be used for other applications, because of it's
simplicity and its small kernel footprint. (Please note that our FATX code
is still in beta).

Can our additional drivers be added to the standard kernel once they are
finished?

Our project website is at http://xbox-linux.sourceforge.net/, we have our
kernel changes in the CVS if you want to have a look at it. I didn't want
to send a patch in this mail already, because we might have to discuss what
way to do our patches first (especially on #ifdef CONFIG_XBOX vs. if (xbox)
{}).

Thanks a lot for your time.

   Michael

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