Re: [GIT PULL] ARM: SoC fixes

[Corentin Labbe]

On Sat, Nov 10, 2018 at 10:09:19AM -0800, Olof Johansson wrote:
> On Thu, Nov 8, 2018 at 7:49 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> >
> > * Olof Johansson <olof@xxxxxxxxx> [181107 09:28]:
> > > On Wed, Nov 7, 2018 at 9:17 AM Linus Torvalds
> > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > > >
> > > > On Wed, Nov 7, 2018 at 9:10 AM Olof Johansson <olof@xxxxxxxxx> wrote:
> > > > >
> > > > > ARM: SoC fixes
> > > >
> > > > Pulled.
> > > >
> > > > > I was a bit too trigger happy to enable PREEMPT on multi_v7_defconfig,
> > > > > and it ended up regressing at least BeagleBone XM boards.
> > > >
> > > > Odd. Did it hit some "may_sleep()" test in a driver that is hidden by
> > > > preempt being off? Otherwise I don't see how/why preempt should fail
> > > > in a board-specific manner..
> > >
> > > The board hangs early during boot and the usual way of collecting
> > > early console doesn't seem to work when attempted (I haven't tried
> > > personally).
> > >
> > > It's one of the major non-SMP platforms covered by tests. I'd be
> > > surprised if it turns out to be truly _board_ specific (and rather
> > > specific to OMAP3), but we don't have enough data yet. Chances are it
> > > either shuffles some timing around or indeed hits a may_sleep() test
> > > somewhere.
> > >
> > > (I just realized I might have missed to attribute Guillaume in the
> > > revert patch. Sorry about that).
> >
> > Looks like we're missing the stdout-path for earlycon, maybe try
> > with the following patch? I can't find my Beagleboard-xm right now,
> > time to clean-up a bit I guess.
> >
> > At least omap3-evm, logicpd-torpedo and n900 all boot with PREEMPT.
> 
> To follow up on this, it turned out to be an issue where the kernel
> outgrew the location it was loaded to, and overwrite the device tree
> on decompression. So, not a code issue.
> 
> It's a known fragile aspect on some of the u-boot setups, and
> something I've been hit by myself on my farm a few times.
> 
> Still, for now we'll keep PREEMPT off until next merge window.
> 

Hello

Note that CONFIG_PREEMPT cause some errors also on sun8i-a83t-bananapi-m3
Already reported https://lkml.org/lkml/2017/12/29/139

Regards