On Tue, Mar 10, 2015 at 12:23:03PM +0000, Hanjun Guo wrote: > On 2015年03月07日 01:47, Lorenzo Pieralisi wrote: > > On Wed, Feb 25, 2015 at 08:39:58AM +0000, Hanjun Guo wrote: > >> From: Al Stone <al.stone@xxxxxxxxxx> > >> > >> ACPI reduced hardware mode is disabled by default, but ARM64 > >> can only run properly in ACPI hardware reduced mode, so select > >> ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64. > > > > Agreed. This will remove unneeded acpica code. I think though, > > you should also check the FADT flag HW_REDUCED_ACPI at boot to > > make sure that the tables are HW reduced compliant. I am flagging > > Agreed, I will add that check on top of this patch set. We explicitly > stated that we are using hardware reduced mode on ARM64 in the doc, so, > how about print some warning message and go on with the boot if we > got the wrong flag HW_REDUCED_ACPI at boot? Why would be boot if the ACPI tables are not HW_REDUCED_ACPI compliant ? To look for trouble :) ? arm64 does not support any other ACPI model, the missing flag should disable ACPI IMO on arm64. You could add a check in this patch same place where you check the FADT version and be done with this. Thank you ! Lorenzo > > this up because I noticed code in core code (not guarded by > > ifdef) that checks: > > > > acpi_gbl_reduced_hardware > > > > and if it is not set it goes on instantiating fixed HW devices. > > > > drivers/acpi/scan.c:2567 > > > > It is just a heads up, I think it is harmless, but one thing is > > removing acpica code on ACPI HW reduced only, the other is to make > > sure the kernel does not try to use ACPI HW features that acpica > > can't support. > > I agree, need some cleanups for the ACPICA code I think, and this > was raised about 1 and half years ago and Intel folks need more > consideration on that [1]. > > [1]: http://comments.gmane.org/gmane.linux.acpi.devel/63844 > > Thanks > Hanjun > -- 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
