From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 19/19] Documentation: ACPI for ARM64
Date: Mon, 28 Jul 2014 19:37:29 +0100 [thread overview]
Message-ID: <20140728183729.GG2576@leverpostej> (raw)
In-Reply-To: <20140728163313.GC32359@quad.lixom.net>
On Mon, Jul 28, 2014 at 05:33:13PM +0100, Olof Johansson wrote:
> On Mon, Jul 28, 2014 at 11:12:29AM +0100, Mark Rutland wrote:
> > On Mon, Jul 28, 2014 at 10:07:50AM +0100, Arnd Bergmann wrote:
> > > On Saturday 26 July 2014 19:34:48 Olof Johansson wrote:
> > > > On Thu, Jul 24, 2014 at 6:00 AM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
> > > > > +Relationship with Device Tree
> > > > > +-----------------------------
> > > > > +
> > > > > +ACPI support in drivers and subsystems for ARMv8 should never be mutually
> > > > > +exclusive with DT support at compile time.
> > > > > +
> > > > > +At boot time the kernel will only use one description method depending on
> > > > > +parameters passed from the bootloader.
> > > >
> > > > Possibly overriden by kernel bootargs. And as debated for quite a
> > > > while earlier this year, acpi should still default to off -- if a DT
> > > > and ACPI are both passed in, DT should at this time be given priority.
> > >
> > > I think this would be harder to do with the way that ACPI is passed in
> > > to the kernel. IIRC, you always have a minimal DT information based on
> > > the ARM64 boot protocol, but in the case of ACPI, this contains pointers
> > > to the ACPI tables, which are then used for populating the Linux platform
> > > devices (unless acpi=disabled is set), while the other contents of the
> > > DTB may be present but we skip the of_platform_populate state.
> > >
> > > If this is correct, then replacing the firmware-generated dtb with a
> > > user-provided on would implicitly remove the ACPI tables from visibility,
> > > which is exactly what we want.
> >
> > That's not quite true.
> >
> > There might not be any DTB, or the user might have provided a DTB with
> > only /chosen/bootargs. Trying to distinguish the many cases of possible
> > DTB is broken as a concept.
> >
> > The EFI stub will attempt to get a DTB from somewhere (provided by
> > filename or as a system table with a magic UUID), and if it can't find
> > one will generate an empty stub DTB.
> >
> > Then it will go and perform some EFI memory setup, placing some
> > properties in the DTB (which might be a stub) describing the EFI memory
> > map.
> >
> > Then we boot the kernel proper, which sees the EFI pointers and looks
> > for an ACPI table. If they are found, ACPI is used. Otherwise we attempt
> > to use the DTB (which might be a stub).
> >
> > Unless ACPI is explcitly disabled, ACPI will be used if present.
>
> Ah, I saw this after I replied to Arnd's email.
>
> The above sounds more like how I envisioned things working, so based on that,
> the default just needs to be flipped and we should be fine (i.e. ACPI needs to
> be explicitly enabled).
Sorry, but I don't follow your reasoning. What is the rationale for
disabling ACPI by default?
That's not going to work for ACPI-only systems which may not have any HW
described in a DTB. I fear it will result in more pain on any systems
which try to ship both ACPI and DT, where ACPI will not get the testing
it requires, leading to a greater possibility of quirks/workarounds
being required later.
Thanks,
Mark.
next prev parent reply other threads:[~2014-07-28 18:37 UTC|newest]
Thread overview: 131+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-24 13:00 [PATCH 00/19] Introduce ACPI for ARM64 based on ACPI 5.1 Hanjun Guo
2014-07-24 13:00 ` [PATCH 01/19] ARM64 / ACPI: Get RSDP and ACPI boot-time tables Hanjun Guo
2014-07-28 18:29 ` Sudeep Holla
2014-07-28 22:49 ` Graeme Gregory
2014-07-29 8:49 ` Sudeep Holla
2014-07-29 13:08 ` Hanjun Guo
2014-07-29 13:50 ` Sudeep Holla
2014-07-29 14:07 ` Hanjun Guo
2014-07-28 18:30 ` Sudeep Holla
2014-07-24 13:00 ` [PATCH 02/19] ARM64 / ACPI: Introduce early_param for "acpi" Hanjun Guo
2014-07-28 18:35 ` Sudeep Holla
2014-07-29 13:10 ` Hanjun Guo
2014-07-24 13:00 ` [PATCH 03/19] ARM64 / ACPI: Introduce lowlevel suspend function Hanjun Guo
2014-07-24 15:34 ` Mark Rutland
2014-07-25 10:42 ` Hanjun Guo
2014-07-28 18:28 ` Sudeep Holla
2014-07-29 13:00 ` Hanjun Guo
2014-07-24 13:00 ` [PATCH 04/19] ARM64 / ACPI: Introduce arch_fix_phys_package_id() for cpu topology Hanjun Guo
2014-07-24 14:43 ` Mark Brown
2014-07-25 10:32 ` Hanjun Guo
2014-07-28 18:51 ` Sudeep Holla
2014-08-01 6:35 ` Hanjun Guo
2014-08-01 10:48 ` Sudeep Holla
2014-07-24 13:00 ` [PATCH 05/19] ARM64 / ACPI: Make PCI optional for ACPI on ARM64 Hanjun Guo
2014-07-24 21:57 ` Naresh Bhat
2014-07-29 16:40 ` Sudeep Holla
2014-07-24 13:00 ` [PATCH 06/19] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init Hanjun Guo
2014-07-29 16:40 ` Sudeep Holla
2014-07-31 3:53 ` Hanjun Guo
2014-07-31 4:22 ` Olof Johansson
2014-07-31 10:23 ` Hanjun Guo
2014-08-20 15:02 ` Grant Likely
2014-08-20 15:00 ` Grant Likely
2014-08-20 15:29 ` Catalin Marinas
2014-08-20 15:43 ` graeme.gregory at linaro.org
2014-07-24 13:00 ` [PATCH 07/19] ARM64 / ACPI: Parse MADT to map logical cpu to MPIDR and get cpu_possible/present_map Hanjun Guo
2014-07-24 23:06 ` Naresh Bhat
2014-07-25 11:11 ` Hanjun Guo
2014-07-30 18:20 ` Sudeep Holla
2014-07-31 8:14 ` Hanjun Guo
2014-08-20 15:14 ` Grant Likely
2014-07-24 13:00 ` [PATCH 08/19] ACPI / table: Print GIC information when MADT is parsed Hanjun Guo
2014-07-30 18:21 ` Sudeep Holla
2014-07-31 8:15 ` Hanjun Guo
2014-07-24 13:00 ` [PATCH 09/19] ARM64 / ACPI: Move the initialization of cpu_logical_map(0) before acpi_boot_init() Hanjun Guo
2014-07-24 15:21 ` Mark Rutland
2014-07-25 10:39 ` Hanjun Guo
2014-07-25 12:18 ` Mark Rutland
2014-07-24 13:00 ` [PATCH 10/19] ARM64 / ACPI: Get the enable method for SMP initialization in ACPI way Hanjun Guo
2014-07-24 15:47 ` Mark Rutland
2014-07-25 10:51 ` Hanjun Guo
2014-07-25 12:24 ` Mark Rutland
2014-07-29 8:12 ` Hanjun Guo
2014-07-31 6:54 ` Olof Johansson
2014-07-31 10:57 ` Hanjun Guo
2014-08-04 9:56 ` Hanjun Guo
2014-07-31 18:52 ` Geoff Levand
2014-08-01 6:49 ` Hanjun Guo
2014-07-24 13:00 ` [PATCH 11/19] ACPI / processor: Make it possible to get CPU hardware ID via GICC Hanjun Guo
2014-07-24 13:00 ` [PATCH 12/19] ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi Hanjun Guo
2014-07-24 13:00 ` [PATCH 13/19] ACPI / table: Add new function to get table entries Hanjun Guo
2014-07-24 13:00 ` [PATCH 14/19] ARM64 / ACPI: Add GICv2 specific ACPI boot support Hanjun Guo
2014-07-24 13:00 ` [PATCH 15/19] ARM64 / ACPI: Parse GTDT to initialize arch timer Hanjun Guo
2014-07-24 13:00 ` [PATCH 16/19] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Hanjun Guo
2014-07-24 13:00 ` [PATCH 17/19] ARM64 / ACPI: If we chose to boot from acpi then disable FDT Hanjun Guo
2014-07-24 13:00 ` [PATCH 18/19] ARM64 / ACPI: Enable ARM64 in Kconfig Hanjun Guo
2014-07-24 13:00 ` [PATCH 19/19] Documentation: ACPI for ARM64 Hanjun Guo
2014-07-24 20:42 ` Randy Dunlap
2014-07-25 10:55 ` Hanjun Guo
[not found] ` <CAFoFrHaWWxRPRYM5+bWj0tGnz05SokqwVGejUCUi+U-KChFBdQ@mail.gmail.com>
2014-07-24 21:19 ` Randy Dunlap
2014-07-29 10:07 ` Christoffer Dall
2014-07-27 2:34 ` Olof Johansson
2014-07-28 8:42 ` Graeme Gregory
2014-07-28 16:23 ` Olof Johansson
2014-07-28 17:44 ` Mark Brown
2014-07-28 9:07 ` Arnd Bergmann
2014-07-28 9:23 ` Graeme Gregory
2014-07-28 10:46 ` Arnd Bergmann
2014-07-28 14:20 ` Andre Przywara
2014-07-28 15:23 ` Arnd Bergmann
2014-07-28 16:14 ` Andre Przywara
2014-07-29 9:17 ` Graeme Gregory
2014-07-29 10:07 ` Arnd Bergmann
2014-07-28 10:12 ` Mark Rutland
2014-07-28 16:33 ` Olof Johansson
2014-07-28 18:37 ` Mark Rutland [this message]
2014-07-28 18:44 ` Olof Johansson
2014-07-28 16:27 ` Olof Johansson
2014-07-28 17:00 ` Mark Rutland
2014-07-28 18:27 ` Olof Johansson
2014-08-12 18:23 ` Catalin Marinas
2014-08-13 23:41 ` Rafael J. Wysocki
2014-08-14 3:21 ` Hanjun Guo
2014-08-14 10:27 ` Catalin Marinas
2014-08-14 20:53 ` Arnd Bergmann
2014-08-15 1:02 ` Olof Johansson
2014-08-15 19:49 ` Arnd Bergmann
2014-08-15 23:19 ` Mark Brown
2014-08-16 12:51 ` graeme.gregory at linaro.org
2014-08-15 9:09 ` Hanjun Guo
2014-08-15 10:01 ` Catalin Marinas
2014-08-18 9:29 ` Hanjun Guo
2014-08-18 12:49 ` Mark Rutland
2014-08-20 22:17 ` Olof Johansson
2014-08-21 4:00 ` Hanjun Guo
2014-07-29 9:01 ` Hanjun Guo
2014-07-28 10:06 ` Mark Rutland
2014-07-28 16:44 ` Olof Johansson
2014-07-28 17:36 ` Mark Rutland
2014-07-28 18:34 ` Olof Johansson
2014-07-29 10:29 ` Christoffer Dall
2014-07-29 10:41 ` Arnd Bergmann
2014-07-29 10:55 ` Mark Rutland
2014-07-29 11:28 ` Mark Rutland
2014-07-29 12:37 ` Christoffer Dall
2014-07-29 12:52 ` Arnd Bergmann
2014-07-29 13:08 ` Mark Rutland
2014-07-29 13:31 ` Christoffer Dall
2014-07-29 14:04 ` Mark Rutland
2014-07-29 14:41 ` Arnd Bergmann
2014-07-29 15:01 ` Christoffer Dall
2014-07-30 6:47 ` Hanjun Guo
2014-07-30 7:14 ` Christoffer Dall
2014-07-30 9:36 ` Hanjun Guo
2014-07-29 13:33 ` Christoffer Dall
2014-07-29 7:58 ` Hanjun Guo
2014-07-29 10:30 ` Christoffer Dall
2014-08-15 22:43 ` Len Brown
2014-08-16 12:45 ` Graeme Gregory
2014-08-20 16:42 ` Grant Likely
2014-07-25 0:46 ` [PATCH 00/19] Introduce ACPI for ARM64 based on ACPI 5.1 Hanjun Guo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140728183729.GG2576@leverpostej \
--to=mark.rutland@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).