On Wed, Apr 23, 2014 at 06:47:05AM +0000, Zheng, Lv wrote: > Hi, Tianyu > > > From: Lan, Tianyu > > Sent: Wednesday, April 23, 2014 1:40 PM > > > > On 2014年04月22日 19:45, Mika Westerberg wrote: > > > On Tue, Apr 22, 2014 at 02:24:15PM +0800, Lan Tianyu wrote: > > >> This patch is to add CONFIG_I2C_ACPI. Current there is a race between > > >> removing I2C ACPI operation region and ACPI AML code accessing. > > >> So make i2c core built-in if CONFIG_I2C_ACPI is set. > > >> > > >> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx> > > >> --- > > >> drivers/i2c/Kconfig | 17 ++++++++++++++++- > > >> drivers/i2c/Makefile | 2 +- > > >> include/linux/i2c.h | 2 +- > > >> 3 files changed, 18 insertions(+), 3 deletions(-) > > >> > > >> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig > > >> index 7b7ea32..c670d49 100644 > > >> --- a/drivers/i2c/Kconfig > > >> +++ b/drivers/i2c/Kconfig > > >> @@ -2,7 +2,9 @@ > > >> # I2C subsystem configuration > > >> # > > >> > > >> -menuconfig I2C > > >> +menu "I2C support" > > >> + > > >> +config I2C > > >> tristate "I2C support" > > >> select RT_MUTEXES > > >> ---help--- > > >> @@ -21,6 +23,17 @@ menuconfig I2C > > >> This I2C support can also be built as a module. If so, the module > > >> will be called i2c-core. > > >> > > >> +config I2C_ACPI > > >> + bool "I2C ACPI support" > > >> + select I2C > > >> + depends on ACPI > > >> + default y > > >> + help > > >> + Say Y here if you want to enable I2C ACPI function. ACPI table > > >> + provides I2C slave devices' information to enumerate these devices. > > >> + This option also allows ACPI AML code to access I2C slave devices > > >> + via I2C ACPI operation region to fulfill ACPI method. > > >> + > > > > > > I'm wondering, can we provide some sort of wrapper function from ACPI core > > > that is guaranteed to be built in to the kernel image and use it instead of > > > adding new Kconfig options? > > > > > Cc: LV > > > > LV tried to fix the issue via wrapper solution in the ACPI code before. > > https://lkml.org/lkml/2013/7/23/87 > > > > He has a plan to resolve the issue in ACPICA later. > > > > Other choice is to increase the i2c-core module count to prevent it > > being unloaded when i2c operation region handler is installed. Remove > > the code When LV finish his job. > > You may see it implemented in ACPICA after several release. > If you need a fix for now, you can use the patch pointed to by the link you've provided, > Or you could find an updated one here: > acpi-ipmi13.patch archived in (https://bugzilla.kernel.org/attachment.cgi?id=112611) > > I think the solution you've provided in this patch is also reasonable for now. > IPMI also uses a similar solution to solve this issue. > Please refer to the CONFIG_ACPI_IPMI. > > The story can be found at: > http://www.spinics.net/lists/linux-acpi/msg49044.html > And the similar solution can be found at: > http://www.spinics.net/lists/linux-acpi/msg49184.html Thanks for the pointers. Given that the IPMI problem was solved like this I guess I2C operation regions can follow the same pattern if there is no better solution available. Out of curiousity: how did you plan to fix this in ACPICA? -- 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
