Hi, > From: Moore, Robert > Sent: Tuesday, October 20, 2015 9:35 PM > > > > > -----Original Message----- > > From: l...@kernel.org [mailto:l...@kernel.org] > > Sent: Monday, October 19, 2015 5:48 PM > > To: sta...@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org; Zheng, Lv; Moore, Robert; Wysocki, > > Rafael J; Zefan Li > > Subject: [PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS > > initialization is performed twice > > > > From: Lv Zheng <lv.zh...@intel.com> > > > > 3.4.110-rc1 review patch. If anyone has any objections, please let me > > know. > > > > ------------------ > > > > > > commit c04be18448355441a0c424362df65b6422e27bda upstream. > > > > ACPICA commit 90f5332a15e9d9ba83831ca700b2b9f708274658 > > > > This patch adds a new FACS initialization flag for acpi_tb_initialize(). > > acpi_enable_subsystem() might be invoked several times in OS bootup > > process, and we don't want FACS initialization to be invoked twice. Lv > > Zheng. > > > > Isn't calling acpi_enable_subsystem more than once essentially an OS bug? > >
I'm not sure if this is an OS bug. And don't know the history of this function. IMO, acpi_enable_subsystem() contains several initialization steps. And the calling order of such steps might be OSPM specific, that's why so many flags are needed for acpi_enable_subsystem(). Then invoking acpi_enable_subsystem() twice at different OS boot stage (early or late) might not be a problem. The patch is a different story, it just fixes an issue that one of the step is called twice in Linux because ACPICA hasn't a flag around acpi_tb_initialize_facs(). Thanks and best regards -Lv > > > > > > Link: https://github.com/acpica/acpica/commit/90f5332a > > Signed-off-by: Lv Zheng <lv.zh...@intel.com> > > Signed-off-by: Bob Moore <robert.mo...@intel.com> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > [lizf: Backported to 3.4: adjust filename] > > Signed-off-by: Zefan Li <lize...@huawei.com> > > --- > > drivers/acpi/acpica/utxface.c | 10 ++++++---- > > include/acpi/actypes.h | 1 + > > 2 files changed, 7 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/acpi/acpica/utxface.c b/drivers/acpi/acpica/utxface.c > > index afa94f5..0985ab7 100644 > > --- a/drivers/acpi/acpica/utxface.c > > +++ b/drivers/acpi/acpica/utxface.c > > @@ -166,10 +166,12 @@ acpi_status acpi_enable_subsystem(u32 flags) > > * Obtain a permanent mapping for the FACS. This is required for the > > * Global Lock and the Firmware Waking Vector > > */ > > - status = acpi_tb_initialize_facs(); > > - if (ACPI_FAILURE(status)) { > > - ACPI_WARNING((AE_INFO, "Could not map the FACS table")); > > - return_ACPI_STATUS(status); > > + if (!(flags & ACPI_NO_FACS_INIT)) { > > + status = acpi_tb_initialize_facs(); > > + if (ACPI_FAILURE(status)) { > > + ACPI_WARNING((AE_INFO, "Could not map the FACS table")); > > + return_ACPI_STATUS(status); > > + } > > } > > #endif /* !ACPI_REDUCED_HARDWARE */ > > > > diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index > > 6d52429..0460073 100644 > > --- a/include/acpi/actypes.h > > +++ b/include/acpi/actypes.h > > @@ -495,6 +495,7 @@ typedef u64 acpi_integer; > > #define ACPI_NO_ACPI_ENABLE 0x10 > > #define ACPI_NO_DEVICE_INIT 0x20 > > #define ACPI_NO_OBJECT_INIT 0x40 > > +#define ACPI_NO_FACS_INIT 0x80 > > > > /* > > * Initialization state > > -- > > 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
