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From: Olof Johansson <olof@lixom.net>
To: Kukjin Kim <kgene@kernel.org>
Cc: Mark Brown <broonie@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	"linux-samsung-soc@vger.kernel.org"
	<linux-samsung-soc@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: Broken device trees for exynos in linux-next
Date: Fri, 16 Aug 2013 09:04:41 -0700	[thread overview]
Message-ID: <CAOesGMiyNM6VdNzKQU3XwoiacJV8hc60mcLiH+vHoS6xJM6q-A@mail.gmail.com> (raw)
In-Reply-To: <13b101ce9a14$2cebd700$86c38500$@org>

On Thu, Aug 15, 2013 at 5:04 PM, Kukjin Kim <kgene@kernel.org> wrote:
> I think, maybe we discussed about that? :) current exynos_defconfig cannot
> support exynos5440 because of LPAE and I remember we decided LPAE and
> non-LPAE should be separated. So as I commented before, exynos5440_defconfig
> is needed. If you have any concerns, please let me know.

Having a SoC-specific defconfig makes no sense. You can run with LPAE
enabled on A15 and A7-based systems even if they don't have enough
memory to need it.

Really, what we want is to just turn on the LPAE functionality and
keep everything else common. Forking into two defconfigs seems like
the wrong idea, even if we did discuss it before. Having something
like a config fragment to include would make more sense, since that
could be shared across all platforms (and apply with
multi_v7_defconfig for those who want to run that on LPAE as well).

Or, you know, just have your build script enable it without having an
in-tree config fragment. That'd work too.

The main case where this isn't sufficient is on platforms where _all_
memory sits above 4G, since you can't boot a non-LPAE kernel on those
at all. It seems like 5440 has memory starting at 2GB so it's not one
of those.


-Olof

WARNING: multiple messages have this Message-ID (diff)
From: olof@lixom.net (Olof Johansson)
To: linux-arm-kernel@lists.infradead.org
Subject: Broken device trees for exynos in linux-next
Date: Fri, 16 Aug 2013 09:04:41 -0700	[thread overview]
Message-ID: <CAOesGMiyNM6VdNzKQU3XwoiacJV8hc60mcLiH+vHoS6xJM6q-A@mail.gmail.com> (raw)
In-Reply-To: <13b101ce9a14$2cebd700$86c38500$@org>

On Thu, Aug 15, 2013 at 5:04 PM, Kukjin Kim <kgene@kernel.org> wrote:
> I think, maybe we discussed about that? :) current exynos_defconfig cannot
> support exynos5440 because of LPAE and I remember we decided LPAE and
> non-LPAE should be separated. So as I commented before, exynos5440_defconfig
> is needed. If you have any concerns, please let me know.

Having a SoC-specific defconfig makes no sense. You can run with LPAE
enabled on A15 and A7-based systems even if they don't have enough
memory to need it.

Really, what we want is to just turn on the LPAE functionality and
keep everything else common. Forking into two defconfigs seems like
the wrong idea, even if we did discuss it before. Having something
like a config fragment to include would make more sense, since that
could be shared across all platforms (and apply with
multi_v7_defconfig for those who want to run that on LPAE as well).

Or, you know, just have your build script enable it without having an
in-tree config fragment. That'd work too.

The main case where this isn't sufficient is on platforms where _all_
memory sits above 4G, since you can't boot a non-LPAE kernel on those
at all. It seems like 5440 has memory starting at 2GB so it's not one
of those.


-Olof

  parent reply	other threads:[~2013-08-16 16:04 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-15 16:43 Broken device trees for exynos in linux-next Olof Johansson
2013-08-15 16:43 ` Olof Johansson
2013-08-16  0:04 ` Kukjin Kim
2013-08-16  0:04   ` Kukjin Kim
2013-08-16  0:35   ` Mark Brown
2013-08-16  0:35     ` Mark Brown
2013-08-16  0:42     ` Mark Brown
2013-08-16  0:42       ` Mark Brown
2013-08-16  3:34       ` Padma Venkat
2013-08-16  3:34         ` Padma Venkat
2013-08-16 16:04   ` Olof Johansson [this message]
2013-08-16 16:04     ` Olof Johansson
2013-08-16 18:03     ` Mark Brown
2013-08-16 18:03       ` Mark Brown
2013-08-17 10:40     ` Kukjin Kim
2013-08-17 10:40       ` Kukjin Kim
2013-08-19 15:15       ` Kevin Hilman
2013-08-19 15:15         ` Kevin Hilman
2013-08-22  9:55         ` Kukjin Kim
2013-08-22  9:55           ` Kukjin Kim
2013-08-22 16:20           ` Olof Johansson
2013-08-22 16:20             ` Olof Johansson

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