On 2020.03.30 15:16, Ard Biesheuvel wrote:
On Mon, 30 Mar 2020 at 16:07, Pete Batard <[email protected]> wrote:
On 2020.03.30 15:01, Ard Biesheuvel wrote:
On Mon, 30 Mar 2020 at 15:56, Pete Batard <[email protected]> wrote:
On 2020.03.30 14:20, Ard Biesheuvel wrote:
On Mon, 30 Mar 2020 at 15:12, Ard Biesheuvel <[email protected]> wrote:
On Mon, 30 Mar 2020 at 15:09, Pete Batard <[email protected]> wrote:
On 2020.03.30 14:06, Ard Biesheuvel wrote:
On Fri, 27 Mar 2020 at 14:06, Pete Batard <[email protected]> wrote:
Incidentally, this is not an [edk2-platform] patch, as the subject line
from previous mail seemed to indicate, but an [edk2] patch.
Do we have a user for this?
Yes we do. I have a pachset lined up that updates the Raspberry Pi ACPI
to 6.3, that has a dependency on this.
But does the RPi have SPE and the associated overflow interrupt?
No, but it doesn't matter since the specs indicate that SPE values can
be set to zero if unused/non-applicable.
ACPI
is designed to be backward compatible, so it is perfectly acceptable
to use the 6.2 macros in the context of a firmware implementation that
complies with 6.3.
This is what happens if you try to use EFI_ACPI_6_0_GICC_STRUCTURE_INIT
in a 6.3 context:
/usr/src/edk2/MdePkg/Include/IndustryStandard/Acpi10.h:297:33: error:
excess elements in scalar initializer [-Werror]
#define EFI_ACPI_RESERVED_BYTE 0x00
^~~~
Building ...
/usr/src/edk2/MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf [AARCH64]
/usr/src/edk2/EmbeddedPkg/Include/Library/AcpiLib.h:64:30: note: in
expansion of macro ‘EFI_ACPI_RESERVED_BYTE’
{EFI_ACPI_RESERVED_BYTE, EFI_ACPI_RESERVED_BYTE,
EFI_ACPI_RESERVED_BYTE} \
^~~~~~~~~~~~~~~~~~~~~~
/usr/src/edk2-platforms/Platform/RaspberryPi/AcpiTables/Madt.aslc:64:5:
note: in expansion of macro ‘EFI_ACPI_6_0_GICC_STRUCTURE_INIT’
EFI_ACPI_6_0_GICC_STRUCTURE_INIT (
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
What do you mean exactly by 'in a 6.3 context': are you trying to
statically initialize a 63 struct with the 60 macro?
Yes. I am trying to upgrade all of our ACPI tables to 6.3, on account
that (part of a commit message from the edk2-platform I have lined up):
-----------------------------------------------------------------------
Because of its widespread availability and low price, we expect the
Raspberry Pi source to be used by platform developers as a starting
point to create their own platform implementation.
As such, it makes a lot of sense to want to use the most up to date
underlying standards, even if the pay off is limited in this case,
as it may help others benefit from the latest improvements and
features brought by modern ACPI.
-----------------------------------------------------------------------
The only reason I'm sending an EDK2 patch, which I'd always rather avoid
so that edk2-platforms patches can be applied faster, is that I haven't
been able to find a way to make the existing 6.0 macros work in a 6.3
context, and I expect that this will be the case for others.
By why do we need the 6.3 context? If 6.0 can describe our platform
fully, it is actually better for compatibility to stick with it rather
than upgrade to 6.3.
See above.
I have to say that I'm a bit taken aback by the idea that, even though
we can anticipate that there will be a need for a 6.3 macro that does
initialise the SPE field, there seems to be strong reluctance to add
that macro before someone makes the case for it.
Well, the reason I asked was because I only want to merge changes that
are actually need. If there is a valid need, I will happily merge this
patch.
But as it turns out, the reason is simply being able to claim that we
implement the latest ACPI revision, which is actually a bad idea for
platforms that don't actually rely on any of the new features, since
it may prevent you from being able to run older OSes
Then we have two very different visions for the platform, especially
when it comes to the Pi 4, where networking and SD card support is
pretty much NO_GO for any "older" OS (and troublesome enough as it is in
modern nones).
This is actually the one place where I'd like to see an actual use-case
made for "older OSes incompatibility", especially when it comes to 6.0
MADT vs 6.3 MADT, where the only different is that 6.0 had 3 reserved
fields and 6.3 started to use 2 of those.
For the record, the MADT blobs we got from Microsoft (for the Pi 3) were
6.0, and we did downgrade them to 5.1 for convenience (rather than
compatibility issues), so I really fail to see the issue with bumping
MADT to 6.3.
Instead, what I'm seeing is folks who need the SPE fields for their
platform and look at other implementations to see how to set them up
wasting time having to send a duplicate of the current to edk2 for very
dubious reasons.
I disagree. We add what we need when we need it. The patch volume is
high enough as it is.
Well, considering that different folks will have to send duplicate
patches, this doesn't entirely come as a surprise...
Sorry, but I really can't see any good reason for this patch to be shot
down. You guys *will* have to process a similar patch sooner or later.
Regards,
/Pete
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