Re: [CFT] Always enable SMP mode on MP capable CPUs - Russell King

From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Tony Lindgren <tony@atomide.com>
Cc: Fabio Estevam <festevam@gmail.com>,
	linux-omap@vger.kernel.org,
	afzal mohammed <afzal.mohd.ma@gmail.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Kevin Hilman <khilman@kernel.org>
Subject: Re: [CFT] Always enable SMP mode on MP capable CPUs
Date: Wed, 31 May 2017 15:59:25 +0100	[thread overview]
Message-ID: <20170531145924.GY23750@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20170531143914.GD3730@atomide.com>

On Wed, May 31, 2017 at 07:39:15AM -0700, Tony Lindgren wrote:
> * Russell King - ARM Linux <linux@armlinux.org.uk> [170527 06:26]:
> > On Fri, May 26, 2017 at 04:52:10PM +0530, afzal mohammed wrote:
> > > Hi,
> > > 
> > > On Thu, May 25, 2017 at 03:13:33PM -0700, Tony Lindgren wrote:
> > > 
> > > > OK so got my am437x-idk back
> > > > 
> > > > And as suspected it won't boot with these changes.
> > > 
> > > Tested here too with your additional changes included & seeing same
> > > behavior here as well on AM437x.
> > > 
> > > As an aside, when Russell posted this patch a week back itself was
> > > suspecting this. i had a certain view on AM437x w.r.t SMP issue back
> > > while officially working on it & since now not officially involved
> > > with the issue at hand, i was uncomfortable dealing with this. But as
> > > Russell's patch was not noticed by others w.r.t AM437x, upon being
> > > able to confirm it yesterday, i at least wanted to bring it to notice
> > > & runaway from the scene.
> > 
> > Right, so I think the summary is: the kernel can't set the SMP bit
> > correctly - it doesn't have the information at this point in time
> > to know definitively whether the bit needs to be set or not.
> > 
> > So, those who are suffering issues with their SMP cores in uniprocessor
> > systems need to ensure that their boot loader correctly configures the
> > CPU cores.
> 
> Russell, current Linux next still has commit e7cf836e9757 ("ARM:
> always enable SMP mode on SMP cores"). You're planning to drop
> it, right?

Please have some patience.

Correct, it should be gone from tonight's linux-next.

The UK has two holidays in May, one of them was this Monday.  I dropped
the patch yesterday, which is the first opportunity since sending that
mail, but due to other pressures yesterday, my tree was in no state to
be pushed out for linux-next's grab last night.

-- 
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