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Date: Tue, 28 May 2024 00:49:16 +0100 (BST)
From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Arnd Bergmann <arnd@kernel.org>, linux-alpha@vger.kernel.org, 
    Arnd Bergmann <arnd@arndb.de>, 
    Richard Henderson <richard.henderson@linaro.org>, 
    Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 
    Matt Turner <mattst88@gmail.com>, Alexander Viro <viro@zeniv.linux.org.uk>, 
    Marc Zyngier <maz@kernel.org>, 
    Linus Torvalds <torvalds@linux-foundation.org>, 
    "Paul E. McKenney" <paulmck@kernel.org>, linux-kernel@vger.kernel.org, 
    Michael Cree <mcree@orcon.net.nz>, Frank Scheiner <frank.scheiner@web.de>
Subject: Re: [PATCH 00/14] alpha: cleanups for 6.10
In-Reply-To: <272a909522f2790a30b9a8be73ab7145bf06d486.camel@physik.fu-berlin.de>
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References: <20240503081125.67990-1-arnd@kernel.org> <272a909522f2790a30b9a8be73ab7145bf06d486.camel@physik.fu-berlin.de>
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On Fri, 3 May 2024, John Paul Adrian Glaubitz wrote:

> > I had investigated dropping support for alpha EV5 and earlier a while
> > ago after noticing that this is the only supported CPU family
> > in the kernel without native byte access and that Debian has already
> > dropped support for this generation last year [1] after it turned
> > out to be broken.
> 
> That's not quite correct. Support for older Alphas is not broken and
> always worked when I tested it. It's just that some people wanted to
> raise the baseline in order to improve code performance on newer machines
> with the hope to fix some minor issues we saw on Alpha here and there.

 I'm not quite happy to see pre-EV5 support go as EV45 is all the Alpha 
hardware I have and it's only owing to issues with the firmware of my 
console manager hardware that I haven't deployed it at my lab yet for 
Linux and GNU toolchain verification.  I'd rather I wasn't stuck with an 
obsolete version of Linux.

> > This topic came up again when Paul E. McKenney noticed that
> > parts of the RCU code already rely on byte access and do not
> > work on alpha EV5 reliably, so I refreshed my series now for
> > inclusion into the next merge window.
> 
> Hrrrm? That sounds like like Paul ran tests on EV5, did he?

 What exactly is required to make it work?

  Maciej