From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 00/17] Introduce ACPI for ARM64 based on ACPI 5.1
Date: Thu, 11 Sep 2014 16:37:39 +0100 [thread overview]
Message-ID: <20140911153739.GA24416@localhost> (raw)
In-Reply-To: <20140911132935.068DCC408F6@trevor.secretlab.ca>
On Thu, Sep 11, 2014 at 02:29:34PM +0100, Grant Likely wrote:
> Regarding the requests to refactor ACPICA to work better for ARM. I
> completely agree that it should be done, but I do not think it should be
> a prerequisite to getting this core support merged. That kind of
> refactoring is far easier to justify when it has immediate improvement
> on the mainline codebase, and it gives us a working baseline to test
> against. Doing it the other way around just makes things harder.
I have to disagree here. As I said, I'm perfectly fine with refactoring
happening later but I'm not happy with compiling in code with undefined
behaviour on ARM that may actually be executed at run-time.
I'm being told one of the main advantages of ACPI is forward
compatibility: running older kernels on newer hardware (potentially with
newer ACPI version tables). ACPI 5.1 includes partial support for ARM
but the S and C states are not defined yet. We therefore assume that
hardware vendors deploying servers using ACPI would not provide such
yet to be defined information in ACPI 5.1 tables.
What if in a year time we get ACPI 5.2 or 6 (or an errata update)
covering the S and C states for ARM? I would expect hardware vendors
to take advantage and provide such information in ACPI tables. Can we
guarantee that a kernel with the current ACPI patches wouldn't blow up
when it tries to interpret the new tables? If we can't guarantee this,
we rather fix it now. Some suggestions:
a) Make sure code which doesn't have a clear behaviour on ARM is not
compiled in and doesn't even try to interpret such tables on ARM (you
could just go for the latter but I'm not sure how feasible it is)
b) Ensure that the current patches don't support anything other than
ACPI 5.1 (6 or later would not be supported; can we get information
about which errata update do vendor tables cover?)
c) Consider the current ACPI code broken for ARM (rather than feature
incomplete) and strongly recommend vendors not to use it
Point (a) looks the sanest to me. Point (b) kind of defeats one of the
ACPI goals while point (c) would question why we even bother discussing
merging now.
--
Catalin
next prev parent reply other threads:[~2014-09-11 15:37 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-01 14:57 [PATCH v3 00/17] Introduce ACPI for ARM64 based on ACPI 5.1 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 01/17] ARM64: Move the init of cpu_logical_map(0) before unflatten_device_tree() Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 02/17] ARM64 / ACPI: Get RSDP and ACPI boot-time tables Hanjun Guo
2014-09-09 16:26 ` Catalin Marinas
2014-09-09 16:41 ` Jon Masters
2014-09-09 16:44 ` Jon Masters
2014-09-09 17:15 ` Mark Rutland
2014-09-09 17:33 ` Jon Masters
2014-09-09 17:50 ` Lorenzo Pieralisi
2014-09-09 18:05 ` Sudeep Holla
2014-09-09 19:06 ` Jon Masters
2014-09-10 11:13 ` Hanjun Guo
2014-09-10 12:33 ` Catalin Marinas
2014-09-10 21:51 ` Grant Likely
2014-09-11 11:01 ` Catalin Marinas
2014-09-14 15:40 ` Grant Likely
2014-09-14 21:59 ` Catalin Marinas
2014-09-15 3:53 ` Grant Likely
2014-09-16 5:29 ` Zheng, Lv
2014-09-10 21:41 ` Grant Likely
2014-09-09 16:54 ` Mark Rutland
2014-09-10 7:30 ` Hanjun Guo
2014-09-10 21:37 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 03/17] ARM64 / ACPI: Introduce lowlevel suspend function Hanjun Guo
2014-09-09 16:35 ` Catalin Marinas
2014-09-09 22:04 ` Graeme Gregory
2014-09-01 14:57 ` [PATCH v3 04/17] ARM64 / ACPI: Introduce early_param for "acpi" Hanjun Guo
2014-09-09 16:37 ` Catalin Marinas
2014-09-09 17:17 ` Bjorn Helgaas
2014-09-09 22:14 ` Jon Masters
2014-09-10 13:04 ` Will Deacon
2014-09-10 13:21 ` Bjorn Helgaas
2014-09-10 18:30 ` Will Deacon
2014-09-10 21:58 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 05/17] ARM64 / ACPI: If we chose to boot from acpi then disable FDT Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 06/17] ARM64 / ACPI: Make PCI optional for ACPI on ARM64 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 07/17] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 08/17] ACPI / table: Print GIC information when MADT is parsed Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 09/17] ARM64 / ACPI: Parse MADT for SMP initialization Hanjun Guo
2014-09-03 17:21 ` Lorenzo Pieralisi
2014-09-04 15:29 ` Hanjun Guo
2014-09-09 4:29 ` Jon Masters
2014-09-09 5:11 ` Hanjun Guo
2014-09-09 5:34 ` Jon Masters
2014-09-09 16:52 ` Lorenzo Pieralisi
2014-09-09 17:00 ` Jon Masters
2014-09-09 17:02 ` Jon Masters
2014-09-09 4:23 ` Jon Masters
2014-09-09 4:57 ` Hanjun Guo
2014-09-09 5:44 ` Jon Masters
2014-09-09 16:00 ` Hanjun Guo
2014-09-09 16:04 ` Jon Masters
2014-09-09 16:14 ` Hanjun Guo
2014-09-11 14:15 ` Will Deacon
2014-09-12 21:30 ` Jon Masters
2014-09-11 10:24 ` Grant Likely
2014-09-01 14:57 ` [PATCH v3 10/17] ACPI / processor: Make it possible to get CPU hardware ID via GICC Hanjun Guo
2014-09-03 16:27 ` Lorenzo Pieralisi
2014-09-08 13:10 ` Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 11/17] ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi Hanjun Guo
2014-09-11 11:08 ` Grant Likely
2014-09-11 11:34 ` Grant Likely
2014-09-12 9:42 ` Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 12/17] ACPI / table: Add new function to get table entries Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support Hanjun Guo
2014-09-01 17:35 ` Marc Zyngier
2014-09-02 8:28 ` [Linaro-acpi] " Alexander Spyridakis
2014-09-02 11:48 ` Tomasz Nowicki
2014-09-02 13:02 ` Marc Zyngier
2014-09-02 15:45 ` Hanjun Guo
2014-09-02 15:59 ` Marc Zyngier
2014-09-02 16:11 ` Sudeep Holla
2014-09-03 10:30 ` Marc Zyngier
2014-09-03 11:17 ` Hanjun Guo
2014-09-04 14:03 ` Hanjun Guo
2014-09-09 6:21 ` Jon Masters
2014-09-03 9:26 ` Tomasz Nowicki
2014-09-03 14:57 ` Arnd Bergmann
2014-09-05 8:52 ` Tomasz Nowicki
2014-09-05 9:47 ` Marc Zyngier
2014-09-05 10:13 ` [Linaro-acpi] " Arnd Bergmann
2014-09-05 10:36 ` Tomasz Nowicki
2014-09-05 10:39 ` Marc Zyngier
2014-09-05 10:49 ` Tomasz Nowicki
2014-09-09 6:27 ` Jon Masters
2014-09-11 13:43 ` Grant Likely
2014-09-02 16:34 ` Catalin Marinas
2014-09-11 11:48 ` Grant Likely
2014-09-11 12:01 ` Marc Zyngier
2014-09-09 6:14 ` Jon Masters
2014-09-03 18:42 ` Arnd Bergmann
2014-09-04 10:10 ` Tomasz Nowicki
2014-09-04 10:14 ` Arnd Bergmann
2014-09-04 10:39 ` Tomasz Nowicki
2014-09-09 6:35 ` Jon Masters
2014-09-01 14:57 ` [PATCH v3 14/17] ARM64 / ACPI: Parse GTDT to initialize arch timer Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 15/17] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Hanjun Guo
2014-09-01 14:57 ` [PATCH v3 16/17] ARM64 / ACPI: Enable ARM64 in Kconfig Hanjun Guo
2014-09-11 15:18 ` Lorenzo Pieralisi
2014-09-01 14:57 ` [PATCH v3 17/17] Documentation: ACPI for ARM64 Hanjun Guo
2014-09-11 13:29 ` [PATCH v3 00/17] Introduce ACPI for ARM64 based on ACPI 5.1 Grant Likely
2014-09-11 13:49 ` Will Deacon
2014-09-12 21:38 ` Jon Masters
2014-09-12 21:43 ` Jon Masters
2014-09-15 4:21 ` Grant Likely
2014-09-11 14:23 ` Rafael J. Wysocki
2014-09-11 14:04 ` Grant Likely
2014-09-11 15:37 ` Catalin Marinas [this message]
2014-09-11 15:57 ` Sudeep Holla
2014-09-11 16:06 ` Graeme Gregory
2014-09-11 16:14 ` Sudeep Holla
2014-09-15 4:31 ` Grant Likely
2014-09-15 9:15 ` Catalin Marinas
2014-09-15 22:48 ` Grant Likely
2014-09-16 10:12 ` Catalin Marinas
2014-09-11 16:05 ` Olof Johansson
2014-09-15 4:37 ` Grant Likely
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