-----Original Message-----
From: fedora-arm-bounces(a)redhat.com [mailto:fedora-arm-
bounces(a)redhat.com] On Behalf Of Matthew Wilson
...snip...
In the meantime, I have some questions. Apologies in advance
if these
seem simple.
1) There are various different kernels from different sources.
I'm
used to there being a small set of "right" kernels (that is,
Fedora's
idea of "right") for x86. I fully appreciate that different
ARM-based
boards are quite different in capabilities (like different
instruction
set variants).
a) Is there likely to be some standardised vanilla Fedora ARM
kernel
source? (Or is that simply the source RPM available for
Fedora?)
Then patches /could/ be offered for the more common systems
(e.g.
Beagle Board & clones, SheevaPlug).
Yes, you can pick up the kernel source rpm for Fedora and use
that.
Alternatively, you could just try the latest stable vanilla
kernel.
b) Would it then make sense to offer these as pre-built RPMs
for common systems?
I guess someone was looking into making this available. In the
meanwhile, kernel images for commonly required boards are
accessible from the Fedora-ARM wiki.
c) Is there any guidance on which version is good to use as a
base?
I've seen quite different kernel versions being used (from
2.6.27 to
2.6.31).
Treat the latest to be the greatest? :-)
2) I understand a little bit about the different calling
conventions,
FP differences (e.g. soft FPU versus VFP), and instruction set
differences (v5 versus v7).
a) Can the kernel can be safely built with a different
instruction set
targeted? (I know there are different optimisation options
passed to
GCC. Apologies if this seems a bit newbie-ish.)
b) For FP-heavy programs (e.g. ogg encoding), is it possible to
build
the packages with VFP/NEON but still get them to work in a soft
FPU
system? I'd imagine any call to an external library would have
to
somehow be defined to use a different calling standard.
I am not entirely sure on this... Anyone?
3) There seem to be some missing dependencies in the packages
in the
current Fedora ARM repository. For example, emacs is requiring
libotf, which doesn't seem to be there in the repository. And
likewise with the xorg-x11-font* packages needing ttmkdir. I'm
confused as to how the RPM could have been successfully built
without
it. What am I missing?
These rpms are now available on koji:
http://arm.koji.fedoraproject.org/koji/buildinfo?buildID=21323
http://arm.koji.fedoraproject.org/koji/buildinfo?buildID=21322
This usually happens because we check for the repoclosure of a
set of package groups. Packages beyond these may have dangling
dependencies. These usually get addressed, during the mass build
run (which will start in this week) or on-demand, like in this
case.
4) I see there has been some discussion over unaligned data
access.
(Oh, I remember that from the ARM2 days.) It seems as if the
Cortex-A8 cores allow unaligned data access when set up to do
so [2].
Does this, in any way, help with the compatibility of packages
targetting Cortex-A8?
You can fix alignment errors in the current versions as well by:
# echo 2 > /proc/cpu/alignment
With hardware support it will be faster.
5) I've managed to get various source packages missing from the
Fedora
ARM repositories to compile successfully (natively). I guess
there is
a reason why there are not in the repos right now -- is that
reason
down to time and priorities, or is there some blocking bugs
with many
of these packages?
As you point out, it is about time and priorities. These will get
addressed in the mass build run that will start this week. If you
provide me with a list of packages I'll move them to the top of
the list.
I look forward to being able to contribute something back into
Fedora!
Great! You are welcome...
Kind regards,
Matthew
Kedar.