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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: al.stone@linaro.org, linux-acpi@vger.kernel.org,
	Hanjun Guo <hanjun.guo@linaro.org>,
	patches@linaro.org, linaro-kernel@lists.linaro.org,
	linaro-acpi@lists.linaro.org
Subject: Re: [PATCH v5 1/5] ACPI: introduce CONFIG_ACPI_REDUCED_HARDWARE_ONLY to enforce this ACPI mode
Date: Wed, 8 Jan 2014 13:46:25 +0100	[thread overview]
Message-ID: <201401081346.25767.arnd@arndb.de> (raw)
In-Reply-To: <1389142011-27356-2-git-send-email-al.stone@linaro.org>

On Wednesday 08 January 2014, al.stone@linaro.org wrote:
> Even though support for X86 in hardware reduced mode is possible, it
> is NOT enabled.  Extensive effort has gone into the Linux kernel so that
> there is a single kernel image than can run on all x86 hardware; the kernel
> changes run-time behavior to adapt to the hardware being used.  This is not
> currently possible with the existing ACPICA infrastructure but only presents
> a problem on achitectures supporting both hardware-reduced and legacy modes
> of ACPI -- i.e., on x86 only.

Not sure about the logic here: While it's certainly possible to build a kernel
that runs on all x86 machines, it's also possible to build one that only
runs on some of them when some basic options are turned off. I don't see
any difference between that and what we have on ARM64 or the multiplatform
subset of ARM32.

I don't think you need any strict architecture dependency here. If you want
to make it harder for users to accidentally turn it on, I'd suggest using

config ACPI_REDUCED_HARDWARE_ONLY
       bool "Hardware-reduced ACPI support only"
       depends on !X86 || EXPERT

	Arnd

  reply	other threads:[~2014-01-08 12:46 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-08  0:46 [PATCH v5 0/5] Hardware Reduced Mode Cleanup for ACPI al.stone
2014-01-08  0:46 ` [PATCH v5 1/5] ACPI: introduce CONFIG_ACPI_REDUCED_HARDWARE_ONLY to enforce this ACPI mode al.stone
2014-01-08 12:46   ` Arnd Bergmann [this message]
2014-01-08 23:55     ` Al Stone
2014-01-09 17:38     ` Catalin Marinas
2014-01-09 21:20       ` Al Stone
2014-01-10 10:37         ` Catalin Marinas
2014-01-10 17:12           ` Al Stone
2014-01-08  0:46 ` [PATCH v5 2/5] ACPI: bus master reload not supported in reduced HW mode al.stone
2014-01-08  0:46 ` [PATCH v5 3/5] ACPI: HW reduced mode does not allow use of the FADT sci_interrupt field al.stone
2014-01-08  0:46 ` [PATCH v5 4/5] ACPI: in HW reduced mode, using FADT PM information is not allowed al.stone
2014-01-08  0:46 ` [PATCH v5 5/5] ACPI: do not map/unmap memory regions for FADT entries in reduced HW mode al.stone

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