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From:   Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Date:   Mon, 15 Mar 2021 17:40:15 -0700
Message-ID: <CALCv0x0EiX-RiH79izHymURxos2SZF+J8GZ1N2AQkrFqiKmY0g@mail.gmail.com>
Subject: Re: [PATCH] MIPS: ralink: select WEAK_REORDERING_BEYOND_LLSC on MT7621
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     John Crispin <john@phrozen.org>,
        linux-mediatek@lists.infradead.org, linux-mips@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Thomas,

On Fri, Mar 12, 2021 at 2:34 AM Thomas Bogendoerfer
<tsbogend@alpha.franken.de> wrote:
>
> On Sun, Mar 07, 2021 at 11:08:06AM -0800, Ilya Lipnitskiy wrote:
> > Upstream a long-standing OpenWrt patch for RALINK MT7621 SoC. Selecting
> > WEAK_REORDERING_BEYOND_LLSC fixes random kernel hangs. This bug and fix
> > was reported by MediaTek WCN division [0].
> >
> > [0]: https://lists.infradead.org/pipermail/lede-commits/2017-August/004537.html
>
> I don't see the Mediatek WCN reporting there. Looking at the 1004K user
> manual I couldn't find a notice about such behaviour. So this looks
> more like a fix for papering over the real bug by just introducing
> a few more syncs. Could you please point me to where this is
> really documented ?
You may actually be right. After doing some testing we may not need
this change after all. Let me drop this patch for now. FYI, the
following commit may have fixed LL SC issues this change was covering
up: https://lore.kernel.org/lkml/20190613134933.048961704@infradead.org/

>
> Thomas.
>
> --
> Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
> good idea.                                                [ RFC1925, 2.3 ]
Ilya