From: Will Deacon <will.deacon@arm.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Al Stone <al.stone@linaro.org>,
"lenb@kernel.org" <lenb@kernel.org>,
Catalin Marinas <Catalin.Marinas@arm.com>,
"robert.moore@intel.com" <robert.moore@intel.com>,
"tony.luck@intel.com" <tony.luck@intel.com>,
"fenghua.yu@intel.com" <fenghua.yu@intel.com>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"devel@acpica.org" <devel@acpica.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linaro-acpi@lists.linaro.org" <linaro-acpi@lists.linaro.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
"patches@linaro.org" <patches@linaro.org>
Subject: Re: [PATCH v3 8/9] ACPI: arm64: use an arch-specific ACPI _OSI method and ACPI blacklist
Date: Thu, 5 Mar 2015 10:17:05 +0000 [thread overview]
Message-ID: <20150305101705.GB5287@arm.com> (raw)
In-Reply-To: <2149383.4T7uuqhSe1@vostro.rjw.lan>
On Wed, Mar 04, 2015 at 11:14:50PM +0000, Rafael J. Wysocki wrote:
> On Monday, March 02, 2015 12:00:21 PM Al Stone wrote:
> > On 03/02/2015 10:29 AM, Will Deacon wrote:
> > > On Wed, Feb 25, 2015 at 12:36:24AM +0000, al.stone@linaro.org wrote:
> > >> diff --git a/arch/arm64/kernel/acpi-blacklist.c b/arch/arm64/kernel/acpi-blacklist.c
> > >> new file mode 100644
> > >> index 0000000..1be6a56
> > >> --- /dev/null
> > >> +++ b/arch/arm64/kernel/acpi-blacklist.c
> > >> @@ -0,0 +1,20 @@
> > >> +/*
> > >> + * ARM64 Specific ACPI Blacklist Support
> > >> + *
> > >> + * Copyright (C) 2015, Linaro Ltd.
> > >> + * Author: Al Stone <al.stone@linaro.org>
> > >> + *
> > >> + * This program is free software; you can redistribute it and/or modify
> > >> + * it under the terms of the GNU General Public License version 2 as
> > >> + * published by the Free Software Foundation.
> > >> + */
> > >> +
> > >> +#define pr_fmt(fmt) "ACPI: " fmt
> > >> +
> > >> +#include <linux/acpi.h>
> > >> +
> > >> +/* The arm64 ACPI blacklist is currently empty. */
> > >> +int __init acpi_blacklisted(void)
> > >> +{
> > >> + return 0;
> > >> +}
> > >> diff --git a/arch/arm64/kernel/acpi-osi.c b/arch/arm64/kernel/acpi-osi.c
> > >> new file mode 100644
> > >> index 0000000..bb351f4
> > >> --- /dev/null
> > >> +++ b/arch/arm64/kernel/acpi-osi.c
> > >> @@ -0,0 +1,25 @@
> > >> +/*
> > >> + * ARM64 Specific ACPI _OSI Support
> > >> + *
> > >> + * Copyright (C) 2015, Linaro Ltd.
> > >> + * Author: Al Stone <al.stone@linaro.org>
> > >> + *
> > >> + * This program is free software; you can redistribute it and/or modify
> > >> + * it under the terms of the GNU General Public License version 2 as
> > >> + * published by the Free Software Foundation.
> > >> + */
> > >> +
> > >> +#define pr_fmt(fmt) "ACPI: " fmt
> > >> +
> > >> +#include <linux/acpi.h>
> > >> +
> > >> +/*
> > >> + * Consensus is to deprecate _OSI for all new ACPI-supported architectures.
> > >> + * So, for arm64, reduce _OSI to a warning message, and tell the firmware
> > >> + * nothing of value.
> > >> + */
> > >> +u32 acpi_osi_handler(acpi_string interface, u32 supported)
> > >> +{
> > >> + pr_warn("_OSI was called, but is deprecated for this architecture.\n");
> > >> + return false;
> > >> +}
> > >
> > > This kinda feels backwards to me. If _OSI is going away, then the default
> > > should be "the architecture doesn't need to do anything", rather than have
> > > new architectures defining a bunch of empty, useless stub code.
> > >
> > > Anyway we could make this the default in core code and have architectures
> > > that *do* want _OSI override that behaviour, instead of the other way around?
> > >
> > We could do that; I personally don't have a strong preference either way,
> > so I'm inclined to make it whatever structure Rafael thinks is proper since
> > it affects ACPI code most. That being said, the current patch structure
> > made sense to me since it wasn't distorting existing code much -- and given
> > the pure number of x86/ia64 machines vs ARM machines using ACPI, that seemed
> > the more cautious approach.
> >
> > @Rafael: do you have an opinion/preference?
>
> My preference is to avoid changes in the existing code at least for the time
> being. Especially if the changes in question are going to affect ia64, unless
> you have an Itanium machine where you can readily test those, that is. :-)
Well, this code doesn't even need to compiled for ia64 if we have those
architectures that want to use _OSI select a Kconfig symbol for it, so I
don't think the testing argument is really that valid. I appreciate that you
want to avoid changing the existing code, but I also don't want to add this
sort of stuff to the architecture code, when it really has nothing to do
with the architecture.
Will
next prev parent reply other threads:[~2015-03-05 10:17 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-25 0:36 [PATCH v3 0/9] Start deprecating _OSI on new architectures al.stone
2015-02-25 0:36 ` [PATCH v3 1/9] ACPI: fix all errors reported by cleanpatch.pl in osl.c al.stone
2015-02-25 12:47 ` Hanjun Guo
2015-03-04 23:04 ` Rafael J. Wysocki
2015-03-04 23:56 ` Al Stone
2015-03-05 0:25 ` Rafael J. Wysocki
2015-03-05 0:06 ` Al Stone
2015-02-25 0:36 ` [PATCH v3 2/9] ACPI: clear up warnings on use of printk reported by checkpatch.pl al.stone
2015-02-25 12:55 ` Hanjun Guo
2015-02-25 20:56 ` Al Stone
2015-02-25 0:36 ` [PATCH v3 3/9] ACPI: clean up checkpatch warnings for various bits of syntax al.stone
2015-02-25 12:59 ` [Linaro-acpi] " Hanjun Guo
2015-02-25 0:36 ` [PATCH v3 4/9] ACPI: clean up checkpatch warnings for items with possible semantic value al.stone
2015-02-25 13:08 ` [Linaro-acpi] " Hanjun Guo
2015-02-25 20:57 ` Al Stone
2015-02-25 0:36 ` [PATCH v3 5/9] ACPI: move acpi_os_handler() so it can be made arch-dependent later al.stone
2015-02-25 13:47 ` [Linaro-acpi] " Hanjun Guo
2015-02-25 0:36 ` [PATCH v3 6/9] ACPI: move _OSI support functions to allow arch-dependent implementation al.stone
2015-03-04 23:09 ` Rafael J. Wysocki
2015-02-25 0:36 ` [PATCH v3 7/9] ACPI: enable arch-specific compilation for _OSI and the blacklist al.stone
2015-03-04 23:11 ` Rafael J. Wysocki
2015-02-25 0:36 ` [PATCH v3 8/9] ACPI: arm64: use an arch-specific ACPI _OSI method and ACPI blacklist al.stone
2015-03-02 17:29 ` Will Deacon
2015-03-02 19:00 ` Al Stone
2015-03-04 23:14 ` Rafael J. Wysocki
2015-03-05 10:17 ` Will Deacon [this message]
2015-03-05 12:56 ` Rafael J. Wysocki
2015-03-04 23:16 ` Rafael J. Wysocki
2015-02-25 0:36 ` [PATCH v3 9/9] ACPI: arm64: use "Linux" as ACPI_OS_NAME for _OS on arm64 al.stone
2015-03-04 23:17 ` Rafael J. Wysocki
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