Ummh... > -----Original Message----- > From: linaro-acpi-bounces@xxxxxxxxxxxxxxxx [mailto:linaro-acpi- > bounces@xxxxxxxxxxxxxxxx] On Behalf Of Moore, Robert > Sent: Wednesday, September 18, 2013 9:38 PM > To: 'Hanjun Guo' > Cc: Box, David E; 'linaro-kernel@xxxxxxxxxxxxxxxx'; > 'patches@xxxxxxxxxx'; 'linaro-acpi@xxxxxxxxxxxxxxxx'; 'Rafael J. > Wysocki'; 'linux-acpi@xxxxxxxxxxxxxxx'; Zheng, Lv; 'Len Brown' > Subject: Re: [Linaro-acpi] [PATCH] ACPICA / hwreg: Use > acpi_gbl_reduced_hardware to prevent accessing PM registers > > While we are at it, here is the *complete* list of ACPICA interfaces > that are meaningless on a hardware-reduced platform. Events are supported by hw-reduced ACPI 5.0, just in a different (non-legacy) way: GPIO-signaled events. So I'm wondering if perhaps a bit of refactoring is in order, rather than complete removal of all those functions? Leo > If we are going to dynamically disable some of these interfaces, we will need to disable > all of them -- for completeness. So, this is actually not a trivial > change. > > I'll let the linux experts chime in on this one. > Bob > > > AcpiInstallSciHandler > AcpiRemoveSciHandler > AcpiInstallGlobalEventHandler > AcpiInstallFixedEventHandler > AcpiRemoveFixedEventHandler > AcpiInstallGpeHandler > AcpiRemoveGpeHandler > AcpiAcquireGlobalLock > AcpiReleaseGlobalLock > AcpiEnable > AcpiDisable > AcpiEnableEvent > AcpiDisableEvent > AcpiClearEvent > AcpiGetEventStatus > AcpiUpdateAllGpes > AcpiEnableGpe > AcpiDisableGpe > AcpiSetGpe > AcpiSetupGpeForWake > AcpiSetGpeWakeMask > AcpiClearGpe > AcpiGetGpeStatus > AcpiFinishGpe > AcpiDisableAllGpes > AcpiEnableAllRuntimeGpes > AcpiInstallGpeBlock > AcpiRemoveGpeBlock > AcpiGetGpeDevice > AcpiGetTimerResolution > AcpiGetTimer > AcpiGetTimerDuration > AcpiReadBitRegister > AcpiWriteBitRegister > AcpiSetFirmwareWakingVector > AcpiSetFirmwareWakingVector64 > AcpiEnterSleepStateS4bios > > > > > > > > > -----Original Message----- > > From: Moore, Robert > > Sent: Wednesday, September 18, 2013 8:09 AM > > To: Hanjun Guo > > Cc: 'Rafael J. Wysocki'; 'Len Brown'; Box, David E; Zheng, Lv; > 'linux- > > acpi@xxxxxxxxxxxxxxx'; 'patches@xxxxxxxxxx'; 'linaro- > > kernel@xxxxxxxxxxxxxxxx'; 'linaro-acpi@xxxxxxxxxxxxxxxx' > > Subject: RE: [PATCH] ACPICA / hwreg: Use acpi_gbl_reduced_hardware to > > prevent accessing PM registers > > > > > > > > > -----Original Message----- > > > From: Hanjun Guo [mailto:hanjun.guo@xxxxxxxxxx] > > > Sent: Wednesday, September 18, 2013 2:32 AM > > > To: Moore, Robert > > > Cc: 'Rafael J. Wysocki'; 'Len Brown'; Box, David E; Zheng, Lv; > 'linux- > > > acpi@xxxxxxxxxxxxxxx'; 'patches@xxxxxxxxxx'; 'linaro- > > > kernel@xxxxxxxxxxxxxxxx'; 'linaro-acpi@xxxxxxxxxxxxxxxx' > > > Subject: Re: [PATCH] ACPICA / hwreg: Use acpi_gbl_reduced_hardware > to > > > prevent accessing PM registers > > > > > > On 2013-9-17 1:26, Moore, Robert wrote: > > > > + #define ACPI_REDUCED_HARDWARE TRUE > > > > > > > > The intent of this feature is of course, to remove all code that > is > > > > not > > > needed -- specifically for hardware-reduced machines where the size > of > > > the kernel is important. > > > > > > > > On a larger machine, the hardware-reduced flag should be > sufficient. > > > However, I would think that the host OS would look at this flag and > > > realize that it should not be doing certain ACPI hardware-related > > > things up front, rather than later when it finds out that a write > to > > > some ACPI hardware fails because the hardware isn't there. > > > > > > Do you mean we should change the ACPI device driver instead of > > > changing the ACPICA code? that would be a hard job, because > hardware > > > ACPI is used everywhere. > > > > > > > > > I don't really know the answer to this, but something tells me that > bad > > things may happen when a driver expects the ACPI hardware to be > there, and > > it finds out that it isn't, simply by calling one of the ACPI > hardware > > interfaces. > > > > Or, we could word it this way: if a driver is expecting the ACPI > hardware > > to exist, and we are running on a hardware-reduced platform, why is > the > > driver being loaded in the first place? > > > > BTW, hardware-reduced is not restricted to ARM platforms. > > > > > > > > > > > Thanks > > > Hanjun > > > > > > > > > > > This is not to say that it is probably a good thing to return an > > > > error > > > from the ACPI hardware code in the hardware-reduced case. > > > > > > > > Bob > > > > > > > > > > _______________________________________________ > 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
