From mboxrd@z Thu Jan 1 00:00:00 1970 From: hanjun.guo@linaro.org (Hanjun Guo) Date: Tue, 06 Jan 2015 19:11:07 +0800 Subject: [PATCH v5 18/18] Documentation: ACPI for ARM64 In-Reply-To: <20150105110533.GA14967@e104818-lin.cambridge.arm.com> References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-19-git-send-email-hanjun.guo@linaro.org> <20141224171815.GD13399@e104818-lin.cambridge.arm.com> <54A90A4C.60908@linaro.org> <20150105110533.GA14967@e104818-lin.cambridge.arm.com> Message-ID: <54ABC2CB.6@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2015?01?05? 19:05, Catalin Marinas wrote: > On Sun, Jan 04, 2015 at 09:39:24AM +0000, Hanjun Guo wrote: >> On 2014?12?25? 01:18, Catalin Marinas wrote: >> [...] >>> >>> In addition to the above and _DSD requirements/banning, I would also add >>> some clear statements around: >>> >>> _OSC: only global/published capabilities are allowed. For >>> device-specific _OSC we need a process or maybe we can ban them entirely >>> and rely on _DSD once we clarify the process. >>> >>> _OSI: firmware must not check for certain _OSI strings. Here I'm not >>> sure what we would have to do for ARM Linux. Reporting "Windows" does >>> not make any sense but not reporting anything can, as Matthew Garrett >>> pointed out, can be interpreted by firmware as "Linux". In addition to >>> any statements in this document, I suggest you patch >>> drivers/acpi/acpica/utosi.c accordingly, maybe report "Linux" for ARM >>> and print a kernel warning so that we notice earlier. >>> >>> ACPI_OS_NAME: this is globally defined as "Microsoft Windows NT". It >>> doesn't make much sense in the ARM context. Could we change it to >>> "Linux" when CONFIG_ARM64? I think we can introduce a Kconfig such as CONFIG_ACPI_OS_NAME_LINUX, selected by ARM64 and change ACPI_OS_NAME to "Linux" when CONFIG_ACPI_OS_NAME_LINUX defined. (we can not add CONFIG_ARM64 in ACPICA code directly since it will be used by windows too) some code like below: diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1f9a20..de567a3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1,5 +1,6 @@ config ARM64 def_bool y + select ACPI_OS_NAME_LINUX if ACPI select ARCH_BINFMT_ELF_RANDOMIZE_PIE select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_GCOV_PROFILE_ALL diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 8951cef..11a10ac 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -369,6 +369,10 @@ config ACPI_REDUCED_HARDWARE_ONLY If you are unsure what to do, do not enable this option. +config ACPI_OS_NAME_LINUX + bool "Using Linux for _OS method" if EXPERT + def_bool n + source "drivers/acpi/apei/Kconfig" config ACPI_EXTLOG diff --git a/include/acpi/acconfig.h b/include/acpi/acconfig.h index 5a0a3e5..db5e13e 100644 --- a/include/acpi/acconfig.h +++ b/include/acpi/acconfig.h @@ -69,7 +69,11 @@ * code that will not execute the _OSI method unless _OS matches the string * below. Therefore, change this string at your own risk. */ +#ifndef ACPI_OS_NAME_USING_LINUX #define ACPI_OS_NAME "Microsoft Windows NT" +#else +#define ACPI_OS_NAME "Linux" +#endif /* Maximum objects in the various object caches */ diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h index 1ba7c19..45d51d2 100644 --- a/include/acpi/platform/aclinux.h +++ b/include/acpi/platform/aclinux.h @@ -69,6 +69,10 @@ #define ACPI_REDUCED_HARDWARE 1 #endif +#ifdef CONFIG_ACPI_OS_NAME_LINUX +#define ACPI_OS_NAME_USING_LINUX 1 +#endif + #include #include #include >> >> We will work on this both on ASWG and linux ACPI driver side, as Dong >> and Charles pointed out, _OSI things can be solved in ACPI spec, when >> that is done, we can modify the kernel driver to fix the problems above. > > Which driver? the ACPICA core driver as you suggested, sorry for the confusion. > > What about ACPI_OS_NAME? Would you suggest it is fine to report > "Microsoft Windows NT" on an ARM system? That _OS_ not _OSI. No, not at all. I prefer "Linux" In include/acpi/acconfig.h, when ACPI_OS_NAME defined, it says: "OS name, used for the _OS object. The _OS object is essentially obsolete,..." for some legacy reasons, we needed "Microsoft Windows NT", but ACPI for ARM64 on linux is totally new, I think we can change it to "Linux" when CONFIG_ARM64 as you suggested. Thanks Hanjun