Re: [Qemu-devel] Linux 3.4, VersatilePB and PCI

[Peter Maydell]

On 13 January 2015 at 10:35, Marc Marí <address@hidden> wrote:
> I was fearing that answer :). No, I can't. I want to compare the
> behaviour of a "normal" Linux 3.4 with another modified Linux 3.4, and
> the second one is fixed.
>
> And is not that ancient, it only has 2.5 years :)

In that case you'll need to debug the issue like you would
any other "kernel misbehaving" issue -- figure out what the
kernel is doing to cause it to print that message, identify
whether that's because the kernel itself is buggy or because
QEMU's hardware emulation is buggy, and go from there...

There were a number of bugfixes applied to the versatile
PCI controller code at some point after 3.4, so I wouldn't
be very surprised if the answer turns out to be "this is
just broken in 3.4".

In particular, commit 9b0f7e39923 which isn't in 3.4 AFAIK
basically says "we broke I/O access", which is probably what
you're running into. I expect you'll need other fixes too.

So you can try to find and cherry-pick the necessary fixes, which
could be painful, or you can move to a newer kernel which already
has them.

-- PMM