On Tue, Dec 03, 2013 at 06:30:48PM -0700, Al Stone wrote: > I thought I could get this to work, but I am going to have to defer > to the ACPICA upstream folks. For the time being, I think that all > of the architectures that want to use ACPI in either legacy mode or > in stripped down reduced HW mode will have to use different kernels, > one for each mode. I thought there might be enough safety checks to > allow the kernel to boot in legacy mode and switch into reduced HW at > boot, but there are not, in my opinion. I don't see a way to make the > switch *and* maintain conformance with the spec without significant > change to ACPICA itself. Ugh. That needs fixing. There's been a huge amount of work done to ensure that x86 only needs a single kernel image for 64-bit, it really needs to be runtime. We shouldn't have merged it in this state. > For example, enforcing that various functions are not allowed while > in reduced HW mode could be done by a check of the reduced HW flag on > entry. If it is set, return the value the function would have returned > had it been stubbed out for reduced HW mode. This is simple enough but > to do so would require modifying at least 29 functions in ACPICA, by my > count, not something upstream is particularly keen on -- nor am I. I'd > rather step back and work with ACPICA over the longer term and see if > there's some way to get this functionality implemented properly instead > of trying to bolt it on somehow. How many of those are calls that we'll actually execute in the HW reduced case? -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- 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
