-----Original Message----- From: fedora-arm-bounces@redhat.com [mailto:fedora-arm- bounces@redhat.com] On Behalf Of Matthew Wilson
...snip...
In the meantime, I have some questions. Apologies in advance if these seem simple.
- 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? :-)
- 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?
- 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.
- 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.
- 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.
[1] http://www.igep- platform.com/index.php?option=com_content&view=article&id=46&It emid=55
[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi 0344j/Beihgifg.html