> -----Original Message----- > From: linaro-acpi-bounces@xxxxxxxxxxxxxxxx [mailto:linaro-acpi- > bounces@xxxxxxxxxxxxxxxx] On Behalf Of Al Stone > Sent: 17 December 2014 00:03 > To: Catalin Marinas; Arnd Bergmann > Cc: linaro-acpi@xxxxxxxxxxxxxxxx; Rafael J. Wysocki; ACPI Devel Mailing > List; Olof Johansson; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: Re: [Linaro-acpi] [RFC] ACPI on arm64 TODO List > > On 12/16/2014 08:27 AM, Catalin Marinas wrote: > > On Tue, Dec 16, 2014 at 11:27:48AM +0000, Arnd Bergmann wrote: > >> On Monday 15 December 2014 19:18:16 Al Stone wrote: > >>> TODO List for ACPI on arm64: > >>> ============================ > [snip..] > >>> 4. Set clear expectations for those providing ACPI for use with > Linux > >>> * Problem: > >>> * Hardware/Firmware vendors can and will create ACPI tables > that > >>> cannot be used by Linux without some guidance > >>> * Kernel developers cannot determine whether the kernel or > firmware > >>> is broken without knowing what the firmware should do > >>> * Solution: document the expectations, and iterate as needed. > >>> Enforce when we must. > >>> * Status: initial kernel text available; AMD has offered to make > >>> their guidance document generic; firmware summit planned for > >>> deeper discussions. > >> > [snip...] > > > > Another example is SMP booting. The ACPI 5.1 spec mentions the > parking > > protocol but I can't find a reference to the latest document. In the > > meantime, we stick to PSCI. > > Hrm. A bug in the spec. > > Every external document mentioned in the ACPI spec is supposed to have > a link that will eventually get you to the source document. All links > in the spec should point here http://www.uefi.org/acpi which in turn > has links to the authoritative original documents. However, it looks > like the parking protocol document pointed to (the "Multiprocessor > Startup" link) may not be the most recent version. The reference in > the spec to the protocol (Table 5-61, Section 5.2.12.14)) also appears > to be useless (it points to http://infocenter.arm.com/help/index.jsp > which doesn't have the document either). I've filed a change request > with ASWG to fix this. I also raised both of these a while back, I expect the next errata release to correct this. > > That being said, the early systems still don't provide PSCI. They will > at some point in the future, but not now. Regardless, I think it's > reasonable for us to say that if you want ACPI support, PSCI must be > used for secondary CPU startup. People can hack something up to get > the parking protocol to work on development branches if they want, but > I personally see no need to get that into the kernel -- and it needs > to be said explicitly in arm-acpi.txt. > > > -- > ciao, > al > ----------------------------------- > Al Stone > Software Engineer > Linaro Enterprise Group > al.stone@xxxxxxxxxx > ----------------------------------- > > _______________________________________________ > Linaro-acpi mailing list > Linaro-acpi@xxxxxxxxxxxxxxxx > http://lists.linaro.org/mailman/listinfo/linaro-acpi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
